Ranko Tsukigime's Longest Day is considered to be a part of Katsuhiro Otomo's 2013 anthology film Short Peace. Ranko Tsukigime's Longest Day follows the story of a girl named Ranko Tsukigime, who is the daughter of the owner of Tsukigime Enterprises, the world's largest parking garage company. Secretly, however, she is also an assassin who plans on killing her father to avenge her mother's death. Pursued by a collective known as The Veiled, she attempts to go about one of her normal missions, her target this time being the yakuza boss Manji Takahashi, but killing him sets off a bizarre chain of events regarding her and her friends' true forms.