Emily O'Brien, the girl with the Iron Touch, is part of the family-by-choice of Griffin, the Duke of Greythorne. He and his cohorts all have unusual powers, powers that others cover, powers that others fear. Emily can, for lack of a better word, channel machinery. An old foe, the Machinist, has her kidnapped by his minions (who are not nearly as cute as the Minions in the Despicable movies) so that she can transplant his brain into a created machine turned human. If she can't/won't do this, the minions will kill all her friends. You know - the old rock vs. hard place scenario. 
 Cross writes very good YA material. The science aspects, if one can accept the basic premise, stay tryue to themselves. The characters do the same, although they grow up a little in each book. They are, after all, old enough in their time to be getting married; they have relationships that mature as they do.