It is a leisure and holiday service space in the mountain forest in the suburb of Thailand. The design starts from the concrete environment. The first thing we consider is what kind of space device can talk with this mountain forest, and can better conform to the terrain and integrate into nature. The special conditions of the site determine the particularity of the building.The other two sides of the building are embedded in the mountain, and the channel of stream and mountain road is still reserved under the overhead butterfly-shaped building. To keep some trees indoors, the vertical structure is designed as a “column courtyard”, which is a pillar in the structural meaning and a “miniature courtyard” with one tree preserved in the spatial meaning. The roof is a stepped slope, which can be used as a forest theater for small scale performances. Interior space is unified by this sloping roof, and it is full of rhythm as the ground elevation changes.