The Ruined Abbey is located just south of Maella Abbey. This dilapidated structure is crawling with new and more dangerous enemies, including the Skeleton and the Walking Corpse. These undead foes are often weak to holy water or certain light-based spells, though you may not have access to many of those yet. The Ruined Abbey is a multi-floor dungeon with several puzzles involving switches and moving platforms. Your objective is to find the Abbot, who is believed to be held captive within.
As you delve deeper, you'll eventually find the Abbot, but he's trapped inside a magical barrier. To free him, you'll need to defeat the monster guarding him: the 'Trap Box'. The Trap Box is a tricky boss. It has high defense and can cast disruptive spells. Focus on dealing consistent damage with the Hero and Yangus, while Jessica uses her Frizz spells. Keep your HP high, as the Trap Box can hit hard. After defeating the Trap Box, the Abbot will be freed. He will then reveal crucial information about Dhoulmagus's next target and the true nature of the curse, setting you on your next major quest.