Sayonara Zetsubou Sensei 2x11

Detective Nozomu Itoshiki is called upon by an investigator Jinroku to cooperate with the serial murder case, which took place in Sakebu Itoshiki's mansion. Sakebu was a famous artist, who was known for taking care of twelve girls in his mansion, but he has recently died of a chronic disease. After finding out that each murder resemebled various scenes of well-known anime, Nozomu initially suspects Kagerō Usui from his deduction. However, he later discovers the hidden truth behind the serial murder in Sakebu's underground storage room. In the second part of the episode, everyone is celebrating the Tanabata by hanging their written wishes on a bamboo tree, but Nozomu is initially doubtful about the Tanabata custom. However, Kafuka Fūra manages to convince him that every wish will eventually come true in the afterlife, even if it seems impossible to achieve in the current life. Suddenly, everyone in Tanabata festival is convinced of her idea, so they begin to form a cult based on her belief.