"Souvenir"

The protagonist, a 54-year-old living solely on memories from the past 10 years, undergoes hypnotherapy with a psychiatrist for a year to recover lost memories from the past 44 years. On January 14th, with no significant progress in the therapy, the protagonist encounters ruins and a young girl while under hypnosis. Feeling a sense of familiarity with the girl he has never seen before, the protagonist mentions this to the doctor, who suggests that it may be related to the lost memories before leaving.

While cleaning his neglected house due to the lengthy therapy, the protagonist experiences a power outage and opens the shed door to light a fire. As he explores the shed, he is suddenly struck by the shock of an earthquake, causing him to faint after being hit by a falling diary. When he regains consciousness, the protagonist finds himself in front of the ruins he saw during hypnosis.

Strangely, the door to the ruins is locked with the protagonist's shed padlock...
"Why is the entrance to the ruins locked with our shed padlock? Is there a connection between the ruins, the girl, and the lost memories?"
As the protagonist explores the ruins, will he be able to recall and piece together his faded memories?