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.