Members of a cult, modeled on Aum Supreme Truth, sabotage a city's water supply, then commit mass suicide near the shores of a lake. Family members (the credited cast, minus Asano) of the perpetrators meet at the lake to observe the anniversary of their loved ones' deaths. They meet a former member of the cult (Asano), who had trained for the water sabotage attack but defected at the last minute. After realizing their vehicles were missing, Asano leads them to the cabin where he and the deceased cult members had trained for the attack, and they pass the night reminiscing about those they'd known and lost, shown cinematically through improvised dialogues and flashbacks. Sakata, the aforementioned surviving cult member and last to see most of the departed alive, and Atsushi (Arata) interrogate one another about Yûko (played by actress/model (person) Ryo (actress)), Atsushi's sister, whom Sakata had asked to run away with him the night before the attack.