Through the Skylight by Ian Baucom

When Jared, Shireen, and Miranda are each given one glittering gift from an old Venetian shopkeeper, they never fathom the powers they are now able to unleash; they never expect that their very reality is about to be utterly upended. And the adventure has hardly begun.

For in another time, centuries earlier, another trio—Rashid, Maria, and Francesca—have been thrown together under terrible circumstances: They have been kidnapped and, along with hundreds of other children, will be sold into child slavery. Unless, that is, they can find some way to save them all.

But all their fates lie in the hands of Jared, Shireen, and Miranda. The future—and the lives—of these three very modern children become entirely intertwined with those of the children from the past. Danger, it seems, has a way of spanning centuries.