The Legend of Zelda: Oracle of Ages/Black Tower

Before the next quest
Visit the Zora village during Zelda's age and lift all the coffins in the crypt. One of them conceals a chest with a Blue Luck ring.

Also, make sure you collected all twelve ../Heart Pieces/ and as many Magic Rings as possible.

Before entering the Black Tower during Ambi's age, you must visit the Maku Tree during Zelda's age. Only then you will receive the Maku Seed, necessary to reach Veran.

Dungeon


The lower floors of the tower are just fighting arenas. At the end of this linear series of rooms, you need the Maku Seed and the eight Essences of Time to dispel the illusionary barrier and continue.

Next is a maze on two floors. From the entrance, take the stairs to the left. Follow the path until you have to make another choice: descend the stairs towards the center, not near the wall. Then, climb the closest staircase. Continue up and down, and keep to the center. You should eventually reach the Owl Statue, that gives a hint about the next puzzle. Backtrack just one staircase and proceed to the exit in the middle.

In the next room, follow the flame that starts behind Link (as the Owl Statue suggested). Proceed to the next terrace and then to the boss room.

Boss:
When Veran falls, the story continues with The Legend of Zelda: Oracle of Seasons. On the contrary, if you already cleared that game and linked it to Oracle of Ages, it is time to face the ../Room of Rites/.