The Shadows of Stars by Samantha Amstutz — book slip

Fate reunited them—but it may yet tear them apart.

Barely surviving a battle with rogue wraiths, Serenna races against time to save Fenn’s life. As he fades with every heartbeat, Vesryn is drawn through their bond, portaling directly into the wraith fortress.

But their reunion is cut short when Lykor, bound by a king's merciless command, is forced to strike against Vesryn. Meanwhile, Jassyn lies abandoned, left for dead after a brutal clash.

Even if they escape unscathed, their battle is far from over. The remaining Heart of Stars must still be reclaimed, and ancient secrets wait to be unearthed on the other side of the world.