Stage 13 (Looking for Proof): Angmar's Tomb
After you reach the locked gate, jump towards the, barely visible, interactive edge on the left. Then, jump towards another edge and leap towards the catch shown in the above screenshot. After you reach the catch mentioned above, this will unlock a blue object above the locked gate. Switch to the other wizard and use his staff to shoot a magic projectile and unlock the passage. Walk into the next location in the tomb....