本作品作为东映制作的特摄电视剧，是继《兄弟拳》以来时隔11年的单发作品。并以破天荒的性格的主人公为首的个性丰富的登场人物而展开的故事。

凉村晓，一位天生乐观、无拘无束(是无责任才对)的「三流」私家侦探，某天他被托去调查最近发生的小学生失踪事件，但在过程中遇上了黑暗族/闇次元界一班野心统治人类世界的怪物，在危急关头凉村晓撞上了为对抗黑暗族而成立的特务机关S.A.I.D.O.C.的机战车，因此变成了超光战士。至此，一位无责任……不，一位新的英雄传说从此誔生。

Kamen Rider 4 is a web series which was released as an accompanying special to the film Super Hero Taisen GP: Kamen Rider 3. It introduced a new rider, Kamen Rider 4, who is the fourth Kamen Rider cyborg created by Shocker after Kamen Riders 1, 2, and 3. The plot goes around a time loop created by the Shocker that resets whenever someone dies, but whenever the loop resets Shocker itself somehow grows stronger and stronger. Thus, it is up to the Riders to decide whether to keep on fighting a useless battle... Or end the loops for good by sacrificing one of their own.