The Mourning Emporium

Two summers ago, Venice was dying and an 11-year-old girl made her first (so she thought) visit to the city where she instantly felt she belonged. Teodora, it transpired, was the undrowned child, destined to save Venice from its long-standing enemy, Bajamonte Tiepolo, the traitor. According to a long ago prophecy, Teo and Renzo (the studious son) were the only people equipped to defeat the baddened magic that the traitor brought to the stricken city.
But they couldn't kill him - and so, subdued, but bitter, he returned to his shadowy existence. Now he's back. And in need of a new army, he sets his sights on London - who are weak with mourning the death of their Queen, Victoria. Teo and Renzo find themselves on board a ship for orphans whose course seems mysteriously set for London. Once again, destiny brings them face to face with their enemy, who will stop at nothing to destroy not only London and Venice but the children at the heart of the prophecy that binds him to his failure.