YIU-MING and PIT-TAT go to the unit 9D to check it out, only to find out that it's heavily locked, so the following day, YIU-MING goes to the unit again at dusk. They wait until midnight and PIT-TAT has already fallen asleep by then. Suddenly, YIU-MING hears someone singing, above which he even sees a shadow flash by near the unit. After learning that PIK-KEI falls ill, YIU-MING specifically goes to visit her. At the same time, a courier delivers the personal belongings of PIK-KEI's late mother, among which there is a gold pendant. With PIK-KEI having a gut feeling that it must be the keepsake given by her biological father, the two start probing into the matter. Though KWAN-NIN returns from Germany, he didn't bring back any gifts for OI-WAH, making her feel a bit disappointed……