The Barren Grounds (The Misewa Saga, Book One) - David A Robertson

Morgan and Eli, two Indigenous children forced away from their families and communities, are brought together in a foster home in Winnipeg, Manitoba. They each feel disconnected, from their culture and each other, and struggle to fit in at school and at their new home until they find a secret portal to another reality. They meet Ochek, the only hunter supporting his starving community who teaches the kids traditional ways to survive.