After leaving the wagon, take the marked route through a narrow opening. Climb to the next section of the storage area.

Listen while two soldiers talk. When one leaves, approach the remaining guard for an assassination.

Continue toward the exit and repeat the approach at the next guarded section. The Watchtower contains a chest after the guard encounter.

Use the ladder to reach the lookout and eavesdrop on the soldiers. Their conversation points you toward Yuanbao's search for Yingying.