Chubby, berated, and belittled by his younger co-workers, Rentaro, a 45-year-old man, yearns for the chance to relive his glory days from high school. "If only I could have one more shot... my life wouldn't be this way..." Despite his claims of past popularity, his colleagues find it hard to believe. Then, one miraculous day, Rentaro finds himself thrust back into his high school years. Could this be his chance to rewrite history and regain his former status? However, his excitement is short-lived when he realizes he's not inhabiting his own body, but that of a normal, unassuming girl from his class. As Rentaro grapples with this unexpected twist, he begins to question the true nature of his past popularity... Was it all a lie?! (Source: Coolmic)

Mashiro has been the target of bullying ever since he started high school. He tries his best to deal with the physical and emotional torment, but his days turn even darker when his younger sister, the only family in his life, goes missing. Discovering that the bullies are involved in her disappearance, Mashiro finds a personal revenge service called "Rental Murderers" and seeks their help to get even. However, he is unable to contact them after he pays their fee using all the money he has saved up for his sister's college fund and assumes he has been scammed. Pushed to his breaking point, Mashiro attempts to end his life but is luckily saved by an unknown woman named Kiyoka who suddenly appears. She claims to be an agent sent by Rental Murderers, and...thus begins an epic journey of revenge! (Source: MangaPlaza)