Utterly introvert, this house is located on the last plot of a desired neighbourhood in the outskirts of Sofia, Bulgaria. The complexity of the program confronts the size of the site thus determining the tree structure of the house. Each of the three stories differs in both size and concealment strategy. The vastest first story is underground yet naturally lit and directly connected to the street and the garden. The compressed and mostly open ground floor together with the small garden is hidden behind the hedge. The privacy and sunlight of the large upper floor are meticulously controlled by big scale sliding panels. Only the simple hovering pigmented zinc volume and the blind entrance are exposed to the street while the rest of the complex structure remains unrevealed. The spaces inside are integrated around the light of the central atrium and pierced by unexpected space connections. The reflective roof of the deep veranda brings back garden view to the interior. The linear underground space of the swimming pool has visual and physical contact with the garden while the bright garage is connected to the rest of the house through an under-stair periscope space.