how do bethany joy lenz and tyler hynes' characters know each other in an unexpected christmas?

In the Hallmark movie An Unexpected Christmas, Bethany Joy Lenz plays Emily and Tyler Hynes plays Jamie. Their characters know each other as a recently broken-up couple who must pretend to be together to avoid upsetting Jamie’s family during Christmas. The ruse begins when Emily arrives in town for work and Jamie, who still has feelings for her, pretends they are dating to keep Emily safe from family suspicion and to secure a favorable Christmas event for Emily’s marketing campaign. Over the week, their pretense brings them back into close contact, revealing lingering feelings and chemistry as they navigate family dynamics and the truth about their relationship.