The Snow Queen Quest is unlocked by performing a number of actions after returning to St. Hermelin High School after the Mikage Hospital, but before leaving through the hole in the wall (which puts the player on the main, or SEBEC, quest). Once the route is unlocked, the player should acquire the Snow Queen Mask, which is then taken by Saeko Takami. Ms. Saeko is then possessed by a malevolent spirit inhabiting the Snow Queen mask, who plans on sacrificing her as a way to bring about the Eternal Night. The Snow Queen then proceeds to freeze over the school and, in order to preoccupy the party until the ritual is finished, raises three towers (Thanatos Tower, Hypnos Tower and Nemesis Tower) and appoints previous victims of the mask, Kumi Hirose, Michiko Matsudaira, and Yuriko Yamamoto, to guard them, challenging the party to best all three towers before the ritual is complete. Likewise, the party is tasked by Philemon to find the shards of the Demon Mirror in order to free Ms. Saeko from the spirit's control. The spirit is eventually revealed to be Tomomi Fujimori, Ms. Saeko's best friend from her high school days, who in turn was being controlled by the Night Queen who haunted the mask.
The Snow Queen Quest was rendered unavailable in the original release of the game by not allowing the player to trigger the flag needed to enter the gym storage and retrieve the mask. However, the data wasn't removed from the game, and it's possible to activate the quest via the use of cheat codes, either by forcibly triggering the flag or placing the Snow Queen Mask directly in the player's inventory. The very first lines of dialogue are translated, indicating that there were plans to include it at some point.
Aside from those first lines however, the dialogue is untranslated and shows as weird symbols because the game's engine cannot render Japanese characters. There are minor visual bugs like a white block around Natsumi Yoshino in the Infirmary and sometimes the characters will randomly revert to their Japanese sprites. There's also a small chance of video cutscenes not playing, which gives the Protagonist the ability to walk around the room but cannot interact with anyone and the game will eventually freeze. There's also the remote possibility of multiple characters occupying the same spot in battle, which can be fixed by changing the party's formation.
Battles remain in English since the part of the game's code responsible for that is unrelated to the Snow Queen Quest. The enemy encounter rate is still reduced for the same reasons. Enemies exclusive to the Quest have localized names, as do their unique skills. The only exception to this is Thanatos' tentacles, which not only keep their Japanese name but the game is able to render it without any problems. Like battles, store and casino menus also keep being in English (though not the shopkeeper's dialogue) and the item prices are in dollars instead of the original yen amount.
There is, however, an obstacle in Revelations takes makes the Quest more difficult. In Thanatos Tower, Mariko sells a Mirror Shard to the party for the price of five thousand yen, which is a fairly reasonable and even cheap. As that exchange happens outside of a store, the amount of money needed doesn't change and unlike five thousand yen, five thousand dollars is an incredibly high amount of money especially considering the reduced money drops.
In the manga adaption of the game, the Snow Queen Quest scenario is compacted and merged into the SEBEC scenario. After confronting Hariti, Setsuko Sonomura sends the party to the original world using a terminal of the DEVA System. However, Aki sensed the teleport and changed their destination from the Deva Yuga to St. Hermelin High School as per Kandori's orders.
The party awakens at school and find it covered in ice. After being attacked by a projection of the Snow Queen and being rescued by Yukino, they find out that after Naoya, Eriko and Maki left to rescue Masao and Kei, a student found the sealed mask, triggering the events of the Snow Queen Quest just like in the game. They are instructed by the Masked Boy that in order to free the school they must defeat the three Guardians.
Out of all Guardians, only the fight with Kumi is detailed. Yuriko is mentioned by Yuka, but Michiko is completely absent. Afterwards, the party fights Queen Asura, who is defeated by Durga's Wolf Fang attack. Following the fight, Yukino rushes to check on Ms. Saeko and is followed by Yuka. The other party members then decide to leave for the Deva Yuga while leaving the other two behind.
- In Persona 2: Innocent Sin, the Snow Queen Quest is mentioned by Yukino Mayuzumi. While retrieving the Phoenix Ranger Featherman R masks from Mt. Iwato, she mentions "another sad story about masks", hinting that the events of the quest, despite being optional, actually happened.
- In the PlayStation version of the game, if the player attempts to visit the school after the events of the Police Station, they will see a cutscene of the Ice Castle surrounded by the three towers and Devil's Peak, hinting that the events of the quest are taking place. This cutscene was removed from the PSP port.