In short: Kamakura, (mc, black hair) struggles with depression and is a social outcast. His new neighbour helps cleaning his apartment, helps Kamakura with his trauma and eventually becomes the mc's love interest.
Anyway... the manga emphasizes the importance of compassion and human connection, highlighting the damaging effects of dismissive attitudes, like those of Kamakura's landlord. It's a reminder to offer support to those struggling, even if their challenges aren't obvious.
This was a refreshing take on social disconnection in BL manga's. (A growing issue, especially in Japan.) Kudos to the author for tackling this relevant topic with sensitivity and depth!!!
The Stranger in the Hoarding House