Perfect Scoundrels by Ally Carter (author) (UK edition)

Katarina Bishop and W.W. Hale the Fifth were born to lead very different lives. Her family are criminal masterminds, while he comes from a glorious dynasty. But both families know how to stay under the radar while getting – or taking – whatever they want. When Hale unexpectedly inherits his grandmother’s billion-dollar corporation, he sees no place for Kat and their old heists in his new role. But Kat won’t let him go that easily, especially after she’s tipped off about an elaborate plot to steal the company’s fortune. Instead of being the conman, now Hale might be the target. Kat is prepared to do the impossible, but first she must decide: is she willing to save her boyfriend’s fortune if it means losing the boy?