A furry alien wiseguy comes to live with a terran family after crashing into their garage.

Sam Alden is the 17-year-old high school star player in baseball who seems to have it all. However, his family notices that he is often bothered with fits of coughing. Worried, his parents decide to take him to the hospital, where they are shocked to find out that he has a life-threatening heart disease. Sam has trouble dealing with his illness, but he pretends to still be a joyful teenager to not have his parents worrying even more than they already do. His health is deteriorating, though, and it is eventually revealed that he needs a heart transplant if he wants to survive. This is the beginning of a long journey, which is mentally and physically exhausting. Sam has countless operations, and tests. The search for a donor seems endless to him. Even before the final operation, Sam is forced to deal with several setbacks in his life.