The True Culprit Revealed: The gentle, unassuming fish-shop/market owner Lee Young-hoon (Seo Dong-gab) was the serial predator who abducted Gye-young 18 years prior. He used Lee Jin-geun with arcade games to lure children into captivity.
The Origin of the Link Transfer: During their shared captivity in the basement, young Gye-young held hands with young Da-hyun and formed a deep bond. In her final moments of sacrifice, Gye-young helped Da-hyun escape through a small window and mentally passed her emotional connection to Da-hyun, asking her to connect with Gye-hoon.
The Father's Fate: Gye-hoon's missing father did not abandon his family out of despair; he had traced the killer years earlier and was murdered and buried in the woods by Lee Young-hoon.
The Freezer Twist: The red refrigerator changed hands multiple times: first used by Da-hyun's family to hide what they thought was Jin-geun's body (after Da-hyun defended herself against his stalker attack), then emptied when he awakened and escaped, and finally used by Young-hoon to stash Jin-geun’s actual corpse after murdering him.
Resolution: Da-hyun regains her memories and confronts her survivor guilt. Lee Young-hoon is unmasked and arrested, while the remains of Gye-young and Gye-hoon's father are recovered and given proper burials. Peace returns to Jihwa-dong as Gye-hoon and Da-hyun move forward together.