During their journey to defeat the Demon King, the Hero's party was halted by the rugged yet mystical "Cave of Love."

Their goal is the legendary treasure sleeping in the deepest part, the "Radiance of Love." It is a power absolutely necessary to defeat the Demon King. However, the price for obtaining the treasure is by no means light. Only "two people at a time" can enter the cave. Furthermore, to reach the treasure chamber, the two must overcome all "10 Trial Rooms" standing in their way.

Having steeled his resolve, the Hero took his companion Guest by the hand, and together they passed through the cave's gates.

In the center of the Trial Room sat a single, mysteriously glowing roulette wheel. The trial given changes according to the roll of the dice (the result of the spin), and the door will never open unless the task is achieved.

—At first, it was a trivial trial, like "holding hands." However, as they moved deeper, the trials testing the pair's bond (and courage) gradually began to heat up.