Enhanced with a mob boss’s serum, Muscle Man is a man of steel and iron. His gang conducts a train robbery, with Muscles using a giant rock to block the tracks. Aborad the Century Limited, Keith Spencer transforms into Captain Flash and stops it from running into the back of the blocked train. Chasing the fleeing gang, Captain Flash is knocked out by Muscles. Determined to lure him out, Captain Flash openly challenges Muscle to a fight - the winner taking one million dollars. Flash is able to bare Muscles' blows and manages to take him in the third round.