The Discarded Heiress And Her Lethal Husband

Kaela, the unloved daughter of the Moon family, is forced to marry Barron, a crippled wealthy heir, in her sister's stead. But neither of the two are simple. Kaela is actually a top mercenary code-named "Phantom". And when she saves Barron on a mission, she finds he's actually pretending to be disabled, and he has been given chronic poison. The couple become alliances to help each other defeat their foes.