For clarification with what context we have now (no spoilers)
There are 3 timelines:
TL1 - Sayoung never awakened and died, J asked Yeseong to make him a memorial dungeon where J's memories of them living together are used (to cope, because he can't keep saving people anymore if his only success is dead). J turns back time successfully because of the apocalypse.
TL2 - This is the timeline that we see in Gaeul's fragment. J died instead and Sayoung turned back time because of the apocalypse. But for some reason, Sayoung is still there wandering about.
TL3 - This is the current timeline, and the last chance for them to solve everything.
Gaeul meets TL2 Sayoung and helps her not get lost, then disappears. TL3 J tries to save her but ends up getting stuck in TL1 J's memorial dungeon, and TL3 Sayoung gets dragged in too. For the memorial dungeon to end, the day has to end. They both get out but is still technically in a memorial dungeon (TL2). They kissed then they try to find Gaeul. TL3 J thinks of the watch and wants to get back to the restaurant to check out its description to find clues.
For clarification with what context we have now (no spoilers)
There are 3 timelines:
TL1 - Sayoung never awakened and died, J asked Yeseong to make him a memorial dungeon where J's memories of them living together are used (to cope, because he can't keep saving people anymore if his only success is dead). J turns back time successfully because of the apocalypse.
TL2 - This is the timeline that we see in Gaeul's fragment. J died instead and Sayoung turned back time because of the apocalypse. But for some reason, Sayoung is still there wandering about.
TL3 - This is the current timeline, and the last chance for them to solve everything.
Gaeul meets TL2 Sayoung and helps her not get lost, then disappears. TL3 J tries to save her but ends up getting stuck in TL1 J's memorial dungeon, and TL3 Sayoung gets dragged in too. For the memorial dungeon to end, the day has to end. They both get out but is still technically in a memorial dungeon (TL2). They kissed then they try to find Gaeul. TL3 J thinks of the watch and wants to get back to the restaurant to check out its description to find clues.