Located in the middle unit of a narrow townhouse, the site suffers from severe daylight shortage along its elongated layout. The core design strategy introduces skylight directly to the basement by cutting floor slabs on each floor, with all functional spaces unfolding along the spreading path of natural light. Ceiling heights interpenetrate across multiple floors, and adjacent spaces at different elevations are connected by staircases to establish diverse spatial connections. Scale, proportion, tone, material, finish and light interweave to endow each space with unique temperament, allowing natural light to flow gently through architectural crevices.