Astronomer Shinichi Tachibana has a secret identity as the superhero "Iron Sharp" and is well beloved by children. When they are attacked by a group of metallic aliens, Iron Sharp drives the aliens away. The resourceful Tachibana helps develop an electric barrier to block the aliens from coming to the Earth. After several losses by the aliens, they announce that they will invade the Earth, throwing the world into a state of panic.

After Professor Kasuga is killed by fiendish aliens for plans to a super-rocketship, his children trek across Japan, protected by the second-oldest brother, Koji, who transforms into the super-cyborg, Silver Mask.

四处流浪的少年矢吹丈（石橋正次 饰），在某贫民区遇到身患残疾的中年大叔丹下段平（辰巳柳太郎 饰）。丹下曾是一名战绩赫赫的拳击手，他敏锐地发现了矢吹身上不可多得的拳击天赋，于是坚持要将其训练成才。不过矢吹对拳击根本没有兴趣，整天和小朋友们挥霍胡闹，最终因斗殴被投入监狱。身陷囹圄的矢吹不改争强好胜的本性，可是极富天赋的他被实力强大、技术精湛的力石彻（亀石征一郎 饰）挫败。在此之后，他收心敛性认真练习拳击，指望有朝一日打败力石。不久，监狱在白木财团支持下举行拳击比赛，矢吹和力石即将迎来宿命的对决……
本片根据高森朝雄（即已故漫画家梶原一騎）和ちばてつや的同名原著漫画改编。