Zashisu

One day, junior high teacher Yamauchi Umi sees a murder case on the news. The victim was Suzuki Yumi, a former classmate from junior high. A few days later, Yamauchi's girlfriend, Tamao Yagisawa, a rookie editor, finds a rejected novel with a plot that closely resembled the murder case. The author's name is Haruto Saeki. Soon, just as in the novel, an invitation for a reunion comes from an old friend…
(Source: Grand Jump, translated)