Wonder Boy in Monster Land/Round 3

Castle
You are in a castle, and unlike other stages, start on the right. Head to the left, jumping over the spikes. Climb up to the second floor.

On the second floor, you can see a bar just above you. To proceed with the game, head to the right, up the stairs, and up to the third floor. Jump up the steps to the top of the area; a replacement hourglass should be nearby.

Before the conveyor belt is a secret shop where you can purchase armor.

Run to the end of the are to fight the Red Knight.