Posted by 'Golden Knight' on my BBS:

Oracle of Seasons: 
  Link rides on Epona through the Lost Woods (sound familiar?)
when he reaches an ancient castle. He goes inside the castle, 
and finds the Triforce. He takes the Triforce, but he is then 
warped to a mysterious land called Holodrum. 
  In this land, Link meets a travelling group, and watches the 
performance of the dancer Din. Din is really the Oracle of Seasons. 
However, a huge tornado appears and kidnaps Din. The tornado is 
caused by the power of Onox, the Demon General. Onox traps Din 
in a crystal, and uses her powers to control the seasons and 
throw the Earth into chaos. He builds up his power, trying to 
make the Earth fall into ruin, and build a world of darkness. 
Link must collect the eight treasures to open Onox's tower and 
rescue Din to restore order to the Earth. 

Oracle of Ages: 
  Link rides on Epona through the Lost Woods (sound familiar?) 
when he reaches an ancient castle. He goes inside the castle, 
and finds the Triforce. He takes the Triforce, but he is then 
warped to a mysterious land called Labyrennu. 
  In this land, Link meets with his old friend Impa, and they go 
to find the singer Nayru. Nayru is really the Oracle of Ages. 
However, a shadow rises out of Impa's body. Impa was actually 
possesed by the Sorceress Veran. Veran then takes over Nayru's 
body, and uses her powers to control time and throw the Earth 
into chaos. She builds up her power, trying to make the people 
of Earth suffer, and build a world of darkness. Link must 
collect the eight treasures to open Veran's tower and rescue 
Nayru to restore order to the Earth. 

Password System: 
  After beating either one of these games, you recieve a 
password. Insert the password into the second game, and you 
will start a 'password game'. The password game begins with 
a new opening sequence. In this, Link doesn't find the 
Castle of the Triforce, as he has already gotten it, but is 
warped to the second land to begin the second test of the Triforce. 
  After beating the first game, you can explore the restored world. 
The same thing happens after you beat the 'password game', except 
in the password game there are even more changes to the restored 
world. People will give you passwords from the beaten password game, 
which you then give to people in the beaten first game for items. 
You then get another password from the first game to transfer the 
items back to the password game. Passwords are recorded in the 
game when you get them by the 'Oracle of Connected Worlds', Farore. 
  Also, after beating the password game, a new final dungeon opens up. 
In it, you face final bosses Twinrova and Ganon, who have 
kidnapped Princess Zelda. After beating this, you get another final 
end sequence, and another password. No one knows what the final 
password is for, however it may be for an upcoming third game.