It's a busy time at Higher for Hire and Rebecca finds herself caught up in so much work, she forgets to take Molly to the zoo. In an attempt to make up for her broken promise, Rebecca suggests Molly spend the day with her at work. Rebecca soon gets tied up speaking to clients and with Baloo and Kit busy unloading cargo for a game hunter named McKnee, Molly quickly feels rejected.
When Wildcat loses control of the crane hauling McKnee's cargo, the crate goes crashing through the dock and the creature being transported escapes unnoticed through a small hole in the side. Molly befriends the Inkaran naming it Henry, but soon discovers he has the ability to grow big when wet and shrink when dry. Molly decides to become Henry's mother, but when Kit points out she can never be its real mom, she decides to help him get home.
Rebecca becomes fearful of her daughter's safety when McKnee mis-informs her that the animal is dangerous and when Molly flies off to the Inkaran's homeland on Henry's back. They manage to catch up in the Sea Duck, but in trying to get them both aboard, Molly slips and could have fallen to her doom if it weren't for Henry.
McKnee reveals his true colours on their arrival at the Valley of the Inkaran as he plots to capture all of the fabled creatures, but some clever thinking on Molly's part soon puts pay to that idea.