The Legend of Zelda: Oracle of Seasons/Temple Remains and Sword & Shield Dungeon

Before the next quest
Now that Link owns the Roc's cape, he can get to the Heart Container in the graveyard.

There is also a chest on Goron mountain.

Holodrum and Subrosia
The Maku Tree cannot suggest where the last dungeon is, but there is only one unexplored area left in Holodrum.

Temple remains and Subrosian volcanoes (part 1)
On the tree stump, change the season to autumn. Go all the way west and north. At the second tree stump, change the season back to winter. You can now reach the nearby Subrosian gate.

In Subrosia, enter the nearby cave. Throw a bomb in the lava pit, so that the Subrosian volcanoes will modify the structure of the temple remains in Holodrum.

Temple remains and Subrosian volcanoes (part 2)
First of all, there is a breakable wall just north from the Subrosian gate. Inside, you can get the last Heart Piece.

Move back to the entrance, and change the season to summer. Explore the temple to the east. Eventually, you'll reach the very top, where a room hosts another Subrosian gate.

In Subrosia, follow the path to the north to the entrance of the dungeon.