How much can change in an instant? Tomodachi (Kari) is a reenvisioning of Gakkou Gurashi! chapters 18-21, the only major difference being the time it takes for one character to arrive on-scene. The results are tragic and often gory as the happy school life of Yuki and her friends unravels in a mess of paranoia and despair.

Thank heavens this is only a doujinshi!