Zashisu summary:

One day, junior high school teacher Yamauchi Umi sees a news report about a murder case. The murderer is Suzuki Yumi, a classmate from junior high school.A few days later, Yamauchi's girlfriend, Tamahuri Yagisawa, a rookie editor of literary books, finds a work that closely resembles the murder in a novel that was unsuccessful in a public contest. The author's name is Haruto Saeki. Soon, just like in the novel, an invitation to a class reunion arrives for an old friend...The first suspense horror volume by Masanori Morita!