Living on a rundown shipwreck, Mr. Fish one day discovers a hyperactive young sea dragon Pip - who had mistaken his home for a junkyard - pilfering his belongings. The heated argument that ensues leaves both their houses in ruin. But there is hope. Embarking on a seemingly impossible quest in search of the mythical "Shimmer" to grant them a wish, there's only one problem: someone else is on the hunt.