Eve Zero is a prequel to Eve Burst Error. Once again, the player controls the two main heroes of the series: the witty and womanizing private investigator Kojiroh Amagi, and the beautiful red-haired secret agent Marina. The events of the game take place shortly before those of Eve Burst Error. Kojiroh is working at Katsuragi Detective Office together with his girlfriend Yayoi. Dr. Nishina, the head of a genetic research facility, hires Kojiroh to investigate the disappearance of his son Shin. At the same time, Marina receives an assignment from her boss Kohno, which involves watching over a representative of an American company. As in all EVE games, the two stories appear unrelated in the beginning and are gradually linked together later in the game. The player needs to switch between the two protagonists frequently in order to advance in the game. The interface consists of a menu that makes it possible to interact with the game world. Beside the traditional "Look", "Talk", and "Go" commands, there are many others, specific to the situation. Being a Japanese-style adventure game, Eve Zero does not feature any puzzles.