Searching for work, they find a small town about to build a new town hall. Mike offers that if he and Mary Anne can't do the job in a single day, the town won't have to pay them.
The scenario describes Mike and Mary Anne's attempt to secure employment by offering a unique incentive: if they can complete the construction of the new town hall within a single day, they won't be paid; otherwise, the town will be obligated to pay them for their work.