Paladin, Who I Thought Was Just a Childhood Friend, Confessed His Lifelong Obsession With Me in a Secret Room of a Dungeon?!

Sera and Rion were close, like a sister and a brother, when they were young.

A certain incident drove them apart, but they find themselves face-to-face after Sera transfers to a new department. Rion has grown into a towering giant and turned into a playboy... and a respectable paladin.
Sera feels an emotional distance from Rion because he has grown into a man who is completely different from the boy she once knew.
The two end up being assigned together on a mission to investigate a dungeon.

Working together on the assignment, they slowly begin to find their way back to how they once were, a long time ago.
However, the suspicious dungeon keeps throwing one trap after another at them.
A slime that melts your clothes and toys with your body... A secret room that won't let you out unless you do certain things...

Rion can no longer bottle up his lifelong feelings for Sera after seeing her be played with...