Tracing their ancestry to a small Dublin town while honeymooning in Ireland, newlyweds Regan and Jack Reilly learn disturbing information about their families, a discovery with which they are aided by Jack's colleagues at the Major Case Squad.

Private detective Regan Reilly investigates the theft of a number of wedding gowns, including her own, while her fiancé Jack, head of the NYPD Major Case Squad, tries to solve a series of bank robberies, unaware that the two cases are intertwined.