大正時代，竈門炭治郎繼承亡父留下的炭業工作，支撐一家七口，在山上過著樸實的生活。某日他做完生意返家後發現全家遭鬼王鬼舞辻無慘屠殺，而妹妹禰豆子變成了鬼。鬼殺隊富岡義勇見狀後本欲斬殺禰豆子，但他在見識到兄妹倆的親情後，推薦炭治郎拜鱗瀧左近次為師。炭治郎經過兩年訓練，學會對抗鬼的呼吸法與劍術，通過考驗加入鬼殺隊。

炭治郎完成首次任務斬殺沼澤鬼後，又接到任務前往淺草，途中他聞到當年家人被殺害時的殘留氣味，炭治郎終於和最初的鬼——鬼舞辻無慘——首次接觸，令炭治郎震驚無慘竟偽裝人類組成家庭。在那之後炭治郎結識與無慘對立的鬼珠世和愈史郎，但突然遭遇到無慘的刺客來襲，解除來襲危機後，炭治郎答應收集鬼的血液要求，與珠世建立起合作關係。

炭治郎接到新任務後，前往傳說中有吃人鬼存在的鼓鬼之家，接續遇見同期的隊士我妻善逸及嘴平伊之助，炭治郎在屋外發現兩個孩子表情十分恐慌，於是前來關心，原來他們的哥哥被惡鬼抓進屋內，為了救回被抓走的人類，進入屋裡的兩人，卻陷入包含十二鬼月「原下弦之陸」響凱在內幾個惡鬼為爭奪稀血而互相殘殺的大亂鬥完成任務後，善逸和伊之助加入炭治郎行列。在結識同伴我妻善逸和嘴平伊之助後，他們前去蜘蛛山支援與「下弦之伍」累的對戰。炭治郎在苦戰之際使出祖傳的呼吸法「火之神神樂」，以及禰豆子覺醒的血鬼術一度扭轉頹勢，最終在義勇助陣下取勝。

由於長期違反隊規帶著身為鬼的禰豆子一同行動，炭治郎被押送往產屋敷耀哉的宅邸進行審判，然而他們早已被產屋敷認可。炭治郎等人在恢復後接受特訓。隨後，炭治郎等人前往無限列車執行下一個任務。

In a distant future, Tetsuro is a human boy who wants his body replaced with a robotic one. This is possible, but to do so he has to reach the Immortal Planet onboard the space train Galaxy Express 999. Maetel, a beautiful and mysterious blonde woman dressed in Russian style, joins him in the long journey through space. Every episode sees our heroes arriving in a new planet's space train station.

Twins Kazuya and Tatsuya, and their neighbor Minami have played together since they were children and built an unbreakable bond. But with puberty, the twins realized something: Minami is a girl, and three is a crowd.

As the trio tries to preserve their relationship, Kazuya's pledge to make Minami's dream come true by taking her to Koshien with his baseball pitching skills makes the slackerish Tatsuya wonder about himself, and his own goals. But Minami has another dream she wants fulfilled, and as the twins continue to push themselves, with Minami in the middle, a life-changing tragedy leads one twin down a path he once never would've considered...