Knights of Riona by KT Webb

In the course of a day, Princess Delia lost her home, witnessed her parents death, and was hurled through a portal to an unfamiliar world. Now, she faces an uncertain future in a land that insists medication will cure her of the memories they see as delusions.

With his commanders dying breath, Taeren was told to protect the royal family at all costs. The queen insists he keep the young princess and mysterious Bloodstone from falling into the wrong hands. When the princess disappears, he must face the truth — if he can’t find her and keep the stone safe, it could mean the end of everything he was sworn to protect.