Cuphead,Mugman,and Chalice receives an invitation from the bakery on the Island. By the time they got here,They arrived at the bakery where the Cookie's inventor,Chef Saltbaker,unveils his recipe for a special dessert called the Wondertart,which has the power to make Chalice whole. He warns them about some foes on the island hold its required ingredients and the brothers sets out to collect them with Chalice's help.
Once the cups return to the bakery with the ingredients, they find Saltbaker in the bakery's cellar. He reveals that the Wondertart requires a living soul baked into it to work and that he has kidnapped Mugman in his spiritual form. Cuphead & Chalice battle against Saltbaker,freeing Mugman,and destroying the bakery in the process.
Saltbaker is arrested for his crimes and sentenced to a form of community service that involves assisting Island's inhabitants with their various problems. Saltbaker changes his way as his sentence near its end,rebuild his bakery once it is served and prepares pastries for everyone,including Cuphead,Mugman,& Chalice.