Catherine is fleeing, accompanied by her mother Jane, from the mutation outbreak that was taking place on the cruise ship they were on vacation. Her father had already been transformed into a mutant, which she had witnessed transform into a slug woman with several tentacles with dicks at the tip protruding from her back. With the constant increase in the number of mutants on the ship, it was becoming increasingly difficult to escape and, when they found themselves cornered, they entered any nearby door and found themselves in the ship's engine room.
Unfortunately for them, there was a mutant already looking for someone to contaminate inside, a hermaphrodite rabbit-taur woman who had two dicks, two heads and four arms. The mutant didn't notice their arrival right away, but when she turned to the pair Jane pushed her daughter to the side, making her fall hidden behind a piece of equipment.
Catherine could do nothing but watch as the rabbit-taur woman reached out to her mother, ripped her clothes off, and fucked her.
After filling Jane with her mutating semen, the mutant left the room looking for more victims without noticing Catherine hiding.
Catherine remained in place as she watched her mother transform. Jane's entire body was absorbed leaving only her head, which acquired three large openings and became completely hollow, and her nose extended and turned into a two foot long horse cock accompanied by balls the size of apples.
Seeing that Jane had become a living strap-on and, in this form, she would be unable to even attempt to go after infecting anyone, Catherine approached her mother. She saw that her mother had her eyes at the waistline and her mouth vertically at the bottom.
"Run Catherine, go before they catch you. Leave me here and just find a safe place." Jane said
"I can't mom. I... I can't leave you lying there on the floor, I have to help you however I can." Catherine said
"How lovely you are. If you really want to be with me then could you do me a favor? I have a very strong desire and this must have something to do with the form I took on as a mutant. They say that those who become mutants have a strong desire to infect others, but all I want is to be used." Jane said
Catherine did as her mother asked, lifting her skirt, taking off her panties and putting her mother in place. Only at the last moment, too late, did she realize that her mother had her pussy on her inner part. Having finished being put, mother and daughter's pussy were being pressed against each other, their clits touching. She had already come into contact with the fluids from her mother's wet pussy and, therefore, Catherine was already resigned to becoming a mutant too, but time passed and nothing happened.
"I'm sorry Catherine, I didn't mean to. I don't understand myself now." Jane said
"No need to feel guilty. But the strange thing is that nothing is happening to me. Why am I not turning into a mutant?" Catherine said
"I don't know. Do you have immunity or did not enough enter your body for you to mutate?" Jane asked
"I think not. Immunity would be genetic and so you or the father would not have been transformed, and as far as I know, any minimal amount of fluid is enough to transform someone into a mutant." Christine said
"Well, it doesn't matter now. Can you do one more favor for your dear mother? I'm too horny and since I can't do anything by myself I would like you to stroke my cock for me." Jane said
Christine felt sorry for her mother and did what she asked, but it was strange that as soon as she started to stroke her mother's dick, she felt the touch and the stimulation."This is weird mom, I feel your dick like it's mine. But..." and stretched her mother out, seeing the spot where their pussies touched "....we didn't merge or anything."
"This must be some property of my mutation. I'm a live strap-on now and somehow we have our feelings shared with each other while I'm being used." Jane said
"That's not bad, that feeling is as if your dick was mine." Catherine said and continued stroking her mother's horse cock until they had a very intense orgasm. The girl could feel the cum come out of her mother's balls and travel all the way up the shaft until it spurted from the tip, meanwhile she held it forward so that nothing landed on her, but she couldn't help but moan very loudly.
After the orgasm Catherine got up and was going to take her strap-on mother off, but she had barely put her down when she heard a voice talking to her. "I knew there was someone else hiding in here. You were trying to pass yourself off as a mutant so you wouldn't be turned into one, weren't you?" it was the rabbit-taur woman who was back and she was saying with her right head. "Let me help you break free, I didn't want to be a mutant either but now I think it's the best thing that happened to me." said her left head.
Catherine put her mother back and the rabbit-taur woman jumped on her, ripped her clothes off saying she wouldn't need it anymore, and forced one of her cocks into the girl's mouth, fucking her until she came, sending tainted cum down to her stomach.
The rabbit mutant stood there watching, eager to see Catherine change, but nothing happened. She then turned the girl around and shoved her other cock into Jane's mouth, which went straight through her and her and her daughter's pussies, thus having both of them fucked at the same time. Even after the mutant came one more time inside Catherine, nothing happened to her. The rabbit-taur insisted and continued fucking the girl, wanting to see her become a mutant, but no matter how much infected mutant semen Catherine received, nothing happened to her.
What they didn't know yet was that, due to Jane's current immune system, her vaginal fluids were a powerful antidote against the mutation liquid that made anyone wearing her totally immune to its effects, but the protection wasn't lasting and the person would be fully vulnerable again just 10 seconds after removing her. This was protection so that she wouldn't end up injured or killed by the transformation of whoever was wearing her.