Snake and Frog

A castle-like ancient Western mansion suddenly appears in the heart of the city. Snake and Frog follow the old professor's back through its heavy iron gate. Inside is vast beyond imagination from the outside, with artifacts from different eras mixed together, and the air is damp and chilly. The old professor's face somehow does not stay in memory even for a moment, only his voice echoes through the corridor. Frog licks her lips with her long tongue, her pupils shining with curiosity. This is the beginning of their first case.

They have a senior-junior relationship; Frog likes to 'lick' Snake as if teasing her. Snake, as a common-sense person, is flustered by Frog's wildness, but gradually gets drawn in by her mysterious charm.

Modern Tokyo, but its fringes are colored by the supernatural. The 'castle' that appears in the very heart of the city seems like an entrance to a distorted otherworld where the rules of time and space are warped. Inside, the castle is maze-like, with relics and cursed items from the past haphazardly placed. The folklore research lab serves as a gentle boundary connecting such oddities with everyday life.

To complete the old professor's assignment—the field work on the castle—and solve its mystery. However, it eventually goes beyond mere academic research, delving into the relationship and past of the two.