Angel Beats! takes place at a high school acting as a limbo for teenagers who have died, but experienced hardships or traumas when alive that they must come to terms with and accept before being given a second chance at life.
Those in the afterlife school can still feel pain as they did when they were alive, as well as dying again, only to awaken later with no injuries.
The story of the Angel Beats! anime series follows the main male protagonist Otonashi, a boy who lost his memories of his life after dying. Upon awakening in the afterlife, he meets the main female protagonist Yuri, who invites him to join the Shinda Sekai Sensen (SSS) (死んだ世界戦線, lit. Afterlife Battle Front), an organization she leads which fights against angel for the cruel fates the SSS members experienced in life.
Their only enemy in the world is the school’s Student Council President popularly known as “Angel”, a being with supernatural powers who appears to be in charge of keeping the status quo and the fight against the SSS.
As the story continues, despite Angel being their enemy, Otonashi is getting along with her. Otonashi talks to Angel instead, who informs him that everyone is dead. Otonashi asks for proof, and then Angel impales him.
The next day, he is killed a hundred times by Noda, and finally, he wakes up in the SSS room, where he meets the core SSS members. There, he joins the SSS, and Yuri briefs Otonashi about the afterlife and the reasons for fighting Angel.