Yasoukyoku ~Nemurenu Yoru no Tame no Nocturne~

Makoto is the conductor of his school band. Along with his 4 band members and a college senpai who is acting as the advisor, they stay over at a summer house to practice before a big performance. One stormy night, while they were resting in the living room, lightning knocks out the electricity, including the light. Suddenly, Makoto feels himself being forcibly kissed by someone whom he can't see and then let go. When the light comes on, Makoto feels shocked and is asked by everyone what's wrong. Strangely, everyone has a guilty look on their face. Makoto wonders which one of them might be the culprit. But soon, he tries to forget about this incidence and start preparing for the performance. Except, strange things keep happening that make his heart unsettled....

[From Aarinfantasy]