When a mother, Katherine, and daughter, Ellie, are at the most stressful of times, they can only imagine how the other's problems could be more difficult. Thanks to the magic from their late father's hourglass, their imagination becomes a reality when they switch bodies and see what it's like to be the other person.

Doctor Baines has been conducting genetic experiments on piranhas and has made them virtually unstoppable. Unfortunately, his assistants, Maggie and Paul, accidentally release the hybrids into the Lost River Lake threatening to destroy everyone in their path. Can they prevent the flesh-eating piranhas from escaping into the ocean and spawning?