Title: “meet your step-sis”
It’s her objective goal to fake it so he cannot marry her step sister (legally speaking)
Her son’s goal is to prove that they are faking it (of course he knows)
And the journey makes her realize that although their engagement was premature, but this young couple have a good chemistry and are mature enough to make their own decision
It resolves when she agrees they were faking it.
And the young couple realise they’d wait until graduation to get married