Victor is the most respected assassin in the country - and also the most expensive. He is the doyen of killers, carrying on the family business established by his grandfather. The problem is that it's not a job where you tend to meet the right girl - and so his domineering mother (who has recently gone to live in a Home) is increasingly worried that he's not going to get an heir to carry on the family business. She nags him about it; and has even taken up knitting, just in case.
By contrast, Rose is a free spirit, a gleeful, joyous thief, who has come up with the ultimate con. She borrows a Rembrandt (a real Rembrandt) and gets a copy of it as well. She meets Ferguson, an art-loving gangster who is determined to buy the painting, and, after he's had it authenticated, she performs a switch - leaving him with the fake. By the time he realizes, she's gone - and Ferguson has only one course of action. He calls Victor.