Dream Knocker: Choco no Kimyou na Bunkasai

Dream Knocker's story revolves around Choco, a first year female high school student in the drama club. Her club is planning to put on the musical play Toy Box for the upcoming school culture festival, with Choco taking the lead role, and the entire club is in the process of rehearsing the play. One day during rehearsal, Choco gets a mysterious phone call on her cell phone from an unknown woman. It turns out this phone call is a prank call taking advantage of a mysterious string of events that occurred five years previous that were related to the same Toy Box play. Before the culture festival begins, Choco and her friends want to solve the mystery of the events of five years before.

(Source: Wikipedia)