The starship Jupiter 2 hurtles through space at near the velocity of light, but still is years away from Earth's neighbourhood. The Robinson family, Major Don West and Dr. Zachary Smith, as well as 'the Robot' have been in space now seven years after departing Earth in October 1997. They have encountered many dangerous and fascinating worlds on their oddessy that seems destined to continue on indefinately.....

Down on the lower deck, the family is asleep. The robot is above monitoring flight systems. However in Penny and Judy's cabin, Penny lies awake, with troubled thoughts. She is 19 years old now, and wonders whether she will ever have a man to love. She looks across at Judy's sleeping form in envy, knowing that Judy and Don are together. Penny remembered that day on Priplanus, the first world they stayed on, when she spied Judy and Don walking off into a forest. She followed them at a discreet distance and watched as they lay down on a soft bed of grass. She desperately fought the urge to run away, as Don and Judy undressed each other, and began to make love. At the age of 12 she did not totally understand what she was watching, as Don and Judy heaved and moaned and gasped with excitement.

Since that time, Penny had watched Don and Judy reguarly, amazed at some of the things she had seen them do to each other. Eventually she began experimenting herself, touching herself in certain places that made her feel good. At night, when Judy had watch duty on the flight deck, Penny would get into bed - without pyjamas and feel herself until she seemed to experience an explosion of pleasure between her legs. She lay there gasping and stroking herself, and then hurriedly put on pyjamas in case Judy - or worse - her mother or fatherwalked in.

After a while curiosity got the better of her, and she looked up some of her father's biological files on the ship's computer. After much searching, she came across files on female sexuality, including several multimedia files that Dad had locked for some reason. Penny had smiled to herself as she easily bypassed her father's lockouts and then opened the files. Her eye's grew wide as color full motion video of the sex act, along with text and spoken descriptions of what was happening burst on to the screen. After a few minutes of searching she found references to masturbation and how to give pleasure to herself, and her curiosity grew ever more....

That was 6 years ago, and Penny now understood all there was to know about sex and females and males. Judy and Don continued to have sex, and Penny continued to watch them when she could, masturbating herself into shattering orgasms each time. She desperately wanted to experience real sex, but who was she to do it with? Don was clearly unavailable, and she knew that brothers and sisters should not do it - so forget Will. There was no one for her, and her loneliness made the lustful ache inside her worse each day.

Now as she lay in bed, she looked at Judy. Judy lay asleep, wearing a short neglige nightdress. The covers had slipped off her, giving Penny a clear view of Judy's pert breasts through her neglige. Penny looked down at her own breasts, running her fingers across her nipples. A flare of tingling excitement passed through her as she stroked them until they were hard, and then she moved her hand down onto her panties. She had started to close her eyes and think about men, when the urge to continue to look at Judy grew within her.

Penny felt herself get wet as she watched Judy's body and without realising it, she soon began to rub her clit and imagine Judy without the neglige, masturbating in front of her. Penny's breathing became quicker as the image of a naked Judy thrusting her fingers deep inside her clit and up her nus became clearer and clearer. Penny continued to tickle her clit through her soaked panties, and now moved a hand down and thrust it inside her vaginal lips. She moaned softly in pleasure as the sensations flowed through her body.

Now the mental image of a naked Judy writhing in pleasure on the bed next to her got up and walked over to Penny's bed, got on it and straddled a now naked Penny whilst continuing to masturbate. The image of Judy bending over her, panting and gasping as she neared orgasm was too much for Penny, who came in a shuddering climax, girlcum spurting through the material of her panties. Penny gasped and shuddered, her body trembling as the mighty orgasm passed over her.

It seemed like forever before Penny realised that her orgasm may have woken Judy. She looked over to see Judy still asleep. But Penny did not sleep that night, and instead continued to look at Judy, imagining possibilities and wondering what she, Penny Robinson, really wanted to happen....

The next morning, Penny got up, stripped off and hopped into the shower. She was soaping herself down when Judy came into the bathroom, still wearing only her nightdress, and began brushing her hair. Penny watched her from inside the showerstall, her hand slowly moving between her legs.

"Are you going to be long in there?" asked Judy.Penny resisted the urge to invite Judy to share the water with her.

"No, I'm almost finished," said Penny, as she thrust a finger in and out of her vulva. As she watched through the misted shower door, she saw Judy remove her nightdress and examine her naked body in front of the mirrror. Penny gasped in excitement as she watched her older sister's ass, and imagined herself licking Judy's anus.

Judy turned around at the noise.

"Are you okay in there Penny?"

"Yes, I'm okay. I guess I have an itchy back and it's driving me nuts", said Penny, thinking to herself, 'are you really ready to try this?'

"Do you want me to scrub it for you, if you can't get at it?" asked Judy innocetly. Penny closed her eyes and tried to decide. Then she heard the shower door opening, and Judy, naked, was standing there.

"Here let me help you" she said. She turned Penny around by the shoulders, and stepped partly into the shower with her. Then taking the soap and a sponge, Judy began rubbing soap over Penny's lower back. Penny shivered in excitement as she felt the warm liquid run down between her ass cheeks.

"You know Penny, its a shame we don't have more males out here. You have a beautiful body" said Judy, as she massaged Penny's back and let her hand slip across her upper buttocks.

"Oh yes, it really needs a rub there", said Penny, and Judy smiled and began massaging her ass cheeks. It was quite obvious to Judy that Penny was turned on, because she was breathing heavily and her eyes were nearly closed. Judy realised what her younger sister's problem was, and she knew she could help.

More interestingly she knew she wanted to help. Judy moved her hand down and rubbed between Penny's ass cheeks, massaging her anus. Penny began to softly moan, and reached a hand behind her to guide Judy's hand, as she leaned back into her sister's arms. Judy gently kissed her younger sister at the base of her neck, and brought her free arm to cup Penny's breasts.

"I've always wanted to do this with you Penny" said Judy, as she squeezed her sister's pink nipples. Judy took her hand from her sister's anus, and cupped the other breast, squeezing them and rubbing them together.

"Kiss your breasts Penny, lick your nipples for me, make me hot" said Judy. Penny bent her head down and began licking her nipples, as Judy moved her hands down to her sister's cunt. Judy began gently stroking Penny's clit with one hand, whilst rubbing her anus with the other. Penny, now resting against her sister's breasts, felt herself move her hips in rythym, desperately wanting Judy to lick her cunt. She turned around to face her sister, and after looking at each other for a moment, the two women kissed each other on he lips, gently at first and then with increasing ardour.

Tounges entwined and probed, as Judy continued massaging her sister's clit with her fingers. The two women held each other close under the stream of water. Then Penny slid her hands down to Judy's ass cheeks and spread them, as she thrust her cunt against Judy's. Judy was breathing quickly, as she kissed around Penny's neck and down onto her breasts.

Judy's tounge darted around Penny's nipples, making them hard and her breasts swollen. Steam and spray made the two women's body's glisten, as Penny leaned back and spread her legs. Judy dropped onto her knees in front of her sister, and kissed over her stomach and thighs. Penny moaned and gasped with pleasure as her sister inserted several fingers into her glistening cunt, and then with her other hand, began masturbating herself.

"I'm going to come Judy" gasped Penny. Judy slowly removed her hand from Penny's clit, allowing her younger sister to edge back from orgasm, but continued to kiss her sister hungrily on the mouth, and with her hands cupped Penny's breasts. Judy then said "Water off", and the computer immediately shut off the spray, leaving the two women clutching at each other in the shower stall, glistening wet. Judy took Penny's hand, and led her out of the alcove and into the bathroom, where they stood in front of the mirror, watching themselves.

Judy dropped down to the floor and pulled Penny down on top of her. Penny straddled her older sister and began rubbing her cunt against Judy's. Judy's breathing quickened and she began moaning softly. Penny bent over and kissed her older sister, and then began licking her neck and breasts, whilst moving her hands down to her cunt. Judy then grabbed Penny's ass cheeks and massaged her anus.

"Oh yes, yes it feels so good Judy" said Penny in between moans and gasps.

"Fuck my ass, please," said Penny as she slid forward until her dripping cunt was positioned over Judy's mouth. Judy inserted two fingers into Penny's anus and begn ass-fucking her younger sister, whilst she licked Penny's cunt at the same time. Penny gasped as her sister's fingers moved inside her rectum. She had never felt anything up there, and it felt absolutely divine, almost like a smaller cunt. Penny began a steady buildup to a massive orgasm, she bucked and heaved as her sister licked and thrust. Penny was dripping a steady stream of girlcum over Judy's face, and the two women watched each other in the mirror as they rubbed their bodies against each other.

Judy now had three fingers in Penny's rectum and was thrusting as quickly as possible, as Penny approached a mighty orgasm.

"I want to do you. Please let me fuck you Judy", said Penny. A stream of girlcum landed on Judy's mouth and she lapped it up. Judy's tounge swirled around Penny's clit and inside her cunt, whilst lapping up her cumjuice.

"You taste so good" said Judy as she stuck a tounge up Penny's cunt.

Penny felt like she was ready to explode. She did not care if she and Judy were making too much noise. She just wanted to come over her sister - to piss her girlcum over Judy's face and breasts. Judy reached up with her other hand and spread Penny's ass cheeks wide, and then pushed Penny forward so her tounge could probe her anus. Her tounge slipped inside and Penny heaved in a flash of heat and excitement. Penny moved forward and lay face down on the floor, her ass up. Judy got behind her and continued to ass fuck and lick her younger sister with one hand and her mouth, whilst finger fucking her cunt. Penny's cunt and ass were dripping with cumjuice as Judy inserted her entire fist into Penny's cunt. Penny cried out in ecstasy as she felt both holes filled with her sister.

"Oh god, god, that is great" said Penny, as Judy slowly at first but then with more vigour moved her fist in and out of Penny's cunt. Penny imagined that it must be like having a giant penis inside her. Judy watched as her hand was bathed in Penny's juice, and suddenly Penny's whole body convulsed in a mssive orgasm. Penny felt herself shoot a great stream of girlcum into her sister's face as she cried out in ecstacy.

"I feel like I'm going to piss myself" gasped Penny as she knelt on the floor, her body shuddering and shaking. She clutched her breasts and squeezed, then brought them up to her mouth and began sucking on them, sucking Judy's girlcum.

She felt Judy's hands and mouth inside her anus and cunt, continuing to thrust, and watched between her spread legs, as Judy licked her ass.

"Go ahead" said a panting Judy as she brought her glistening cunt between Penny's legs. At that point Penny just simply lost control, and released a long stream of yellow piss at Judy's cunt, sending her into uncontrollable moaning.

Judy rubbed the urine into her cunt moaning loudly, as Penny turned around and buried her face between her sister's legs, using her tounge on her sister's clit and anus. Judy began shaking as she felt herself begin to orgasm. A flow of girlcum ran off Judy's breasts.

"I want to piss on you Penny" said Judy huskily. Penny quickly placed her breasts over Judy's cunt and a solid stream of urine splashed over them. Penny held her breasts against the flow, rubbing the liquid into Judy's clit and anus. It was too much for Judy, and she came with almost a scream of pleasure.

Judy seemed to come forever, her body shaking, her head swinging back and forth and as Penny watched her sister writhing in excitement under her, and knew she had found the person she needed the most. Penny waited until her sister's orgasm had subsided and then lay down between her legs, nestling her head between Judy's soaked breasts. They kissed passionately and then held each other close.

"I watched you last night Penny, as you masturbated. I knew you wanted me, and I have always wanted you. Don and I will always love each other, but you and I have something special now." said Judy.

Penny looked lovingly into her sister's face. "Can we do this again?" she asked?

"Yes my dear, there is much we can do tgether" said Judy. The two women lay close to each other, watching themselves in the mirror.

The Jupiter 2 sped through space towards new worlds and new adventures.....