Ordinary girl Ellana, to uncover the truth about her older sister who vanished in a car accident, signs a one-year substitute marriage contract with Caskin, president of the imperial tech group. At first they probe and guard against each other; Caskin carries the grief of his brother's death, cold and suspicious, while Ellana is calm and clever, tracing clues step by step. As they grow closer, they heal each other's wounds and join forces against the malicious schemes of their rival Alden. Ellana holds her bottom line—she doesn't rely on dependence for advantage but uses her wits to unravel the hidden truth of that accident. The two shed the barrier of their transaction, learn respect and sincerity, and together guard their career and justice, completing a mutual redemption and earning an equal, genuine affection.
