Marble Freeman, a herbalist from the mountains, saves Declan Burnell's life by chance. To gain access to the Burnell family's herb-cultivation secrets, Marble reluctantly agrees to a 99-day marriage contract with Declan, who is also coerced into the arrangement by his grandfather. After the contract ends, they part ways, but with an agreement that Marble will seek revenge for her mother before they contemplate a possible reunion.
Joelle Gale agreed to marry Charles Frank as a substitute to bring him luck, using her medical expertise to treat his illness while honoring their contract. As they spent more time together, their bond grew deeper, and Joelle gradually unveiled her secret identities, leaving the Gale family humiliated. In the end, she uncovered the truth about her own origins and found lasting happiness with Charles.