S1·E16 Down and Out in Academy Hills

Hercules, Jason, and Iolaus rescue a drowning man after he literally falls from the sky. The funny thing is the man has no idea who he is or where he came from. Hercules soon discovers that the man is actually his half-brother Hephaestus, the God of Steel, and that he's being punished by his mother, Hera, by turning him into a mortal man.