

As the only daughter of the Merrick family, Kirsty Merrick bears the responsibility of marrying into the prestigious Bartley family to lead the Merrick family to new heights, as carefully orchestrated by her mother Evanna Taylor. Kirsty successfully secures a betrothal with Morgan Bartley, the playboy son of the Bartley family's second heir. Unknown to Kirsty, Morgan has been secretly involved with Jess Merrick, Kirsty's only friend who grew up with her in an orphanage. Years later, when brought back to the Merrick family, the kindhearted Kirsty could not bear to abandon Jess, and thus pleaded with her parents to take Jess in as well. Now, Jess has begun an affair with Kirsty's fiance Morgan. To get back at Morgan, Kirsty designs a plan to seduce and intoxicate Nicolai Bartley, the young CEO of the Bartley Group, leading to the start of a dangerous "underground affair."

Fiona Quest, heiress of the Quest family, is seen as a reckless socialite but secretly protects her family's legacy. Concerned by scandals, her grandmother assigns Sean Granger to "reform" her. Unknown to all, Sean is the Granger heir Fiona once saved, and he has long harbored feelings for her. As they grow closer, affection blooms. Together, they expose Sheri Quest's schemes, restore justice, heal the feud between families, and find love with each other.