The episode begins with Sunraku explaining his Ducusram swords, which had already been enhanced through Ascension in previous episodes. He emphasizes their VIT optimization and the neutralization of VIT penalties on critical hits.

However, the seemingly routine battle against the fishman hordes takes a dramatic turn when the NPC Stude unexpectedly charges into the fight. Suddenly, it becomes clear: this is not a simple boss battle but an escort mission where Stude must be protected.

The tension reaches its peak as the gigantic Ctarnidd emerges from the abyss. Its appearance not only causes chaos in the battle but also violently drags the group into a bonus scenario: the abyssal capital of Ruluiath.

Ruluiath is a surreal, upside-down city where the seabed looms above the buildings and the sky lies beneath. In this environment, Sunraku must not only contend with new enemies like the Mermesis Bagroon (flying mermaids with debuffing songs) but also with a 170-hour countdown.

The introduction of Araba, a wounded merfolk, expands the plot. Araba explains the city's inversion and searches for a lost weapon.