A father reminisces about his childhood when he and his younger brother moved to a new town with their mother, her new husband and their dog, Shane. When the younger brother is subjected to physical abuse at the hands of their brutal stepfather, Mike decides to convert their toy trolley, the "Radio Flyer", into a plane to fly him to safety.
(SPOILERS) nothing is shown, or even explained. it's kind of open-ended, with Mikey telling his kids that Bobby flew away, but the implication seems to be that the king killed Bobby, and Mikey just kind of wrote in a happier, more whimsical ending to tell his kids
'The King' beats the younger boy on a regular basis, and at one point violently attacks him (not shown to the audience) to the point he is sent to the hospital.