When Hong Da-Hao, a former gangster turned debt collector, arrives at a struggling bookstore to collect on an overdue debt, he finds the owner has already fled. Though his methods are now bound by the company’s "legal debt collection" rules, Da-Hao is determined to use this job as a turning point in his life. Faced with a near-empty cash register, store manager Liu Qing-Wen pleads for leniency, as the dismal financial situation has shown the reason of the missing bookstore owner.

Seeing this as his only chance to succeed, Da-Hao makes an unconventional decision: he moves into the bookstore, giving himself three months to help Liu Qing-Wen sell off the entire inventory to repay the debt.

But reality is harsh. As Da-Hao quickly realizes, the bookstore’s struggles are real, with foot traffic and sales far below what’s needed. Despite their vastly different backgrounds and conflicting perspectives, the two devise various creative strategies to draw in customers. As they work together, their mutual understanding grows, and so does a budding attraction.
However, just as things begin to look up, shadows from their pasts come back to haunt them...

A gripping tale of redemption, unlikely partnerships, and the power of second chances, A Debt to Settle explores the lengths one will go to rewrite their fate—against all odds.