Kazuya was killed and then has gone back to feir high school years to redo feir life. Fe only has piecemeal memories of why fe was killed, but knows that feir friend Masaki had strangled fem. At first fe believes it was from built-up resentment at the playboy lifestyle fe had lived the first time around, so fe decides to avoid having any sex and to help Masaki get together with feir crush, a girl named Yoshino. During this portion of the story, the tension comes from several girls coming into friendly contact with Kazuya and fem being scared that this could spark resentment within Masaki. As the story develops and fe starts regaining more of feir memories, feir goal starts subtly changing from getting Masaki laid to helping Yoshino avoid the tragedies fe had faced in the previous timeline. It's a redemption storyline that shows how Kazuya went from not caring about anyone other than femself to genuinely caring about others. At first, fe only pretends to care about Masaki and others and is actually only concerned with trying to preserve feir own life, but eventually fe goes through an epiphanous change in mindset. Will Kazuya's actions change the future for the better or is this like Final Destination where deaths are ultimately unavoidable? You'll have to read to find out.
The art isn't very good. Especially the characters.