The Argentinean Butterfly Mystery: C.M.B. vol. 13-14 by Motohiro Katou

Motohiro Katou's C.M.B. vol. 13 comprises of four, one-chapter stories starting with one of those human, heart-shaped puzzles, "The Grass in Summer," which begins when soaring temperatures end the school day early for the students of Meiyuu Private High School – leading to an unexpected discovery in the streets. Sakaki Shinra, Nanase Tatsuki and their friends accidentally stumbled across a small, empty plot of land that was practically hidden from sight ("...surrounded by buildings and is only connected to the main road by a small gap...").What's really peculiar about that plot of land are the various plants and flowers growing on it. Such as arnoglossa, "a type of grass that grows on solid ground," growing in a straight line, morning glory wrapping itself around a water tap and much more. The plot is like coming across a desert oasis in the middle of a city or finding a botanical garden in your attic. When they return to the plot, they meet a woman who tells them the plot of land…