Netta Becker and the Timeline Crime by Jennifer Claessen

A mysterious labyrinth. A desperate king. A rebellious princess.
 
Being stuck in a crumbling old villa in Crete with her annoying, history-obsessed little brother Remy isn’t exactly Netta’s idea of a fun summer holiday. But before she can even get bored, Netta starts having very real dreams where she is dragged back thousands of years to Ancient Greece. Here, King Minos is preparing for the opening of his precious labyrinth, and there are rumours that a monster lurks inside.
 
As Netta becomes more drawn to the past, her present-day self starts slipping away. Netta and Remy must figure out what is pulling her back before they run out of time - and if they don’t solve the puzzle soon, Netta might just become history herself.