"Welcome, ghost of humans, to lunar base 13, the "Garden"." 2199 A.D. Progress in sciences has finally allowed androids to observe the soul of humans, also known as "Ghost." Resolving the ghosts' sorrows and regrets, this role is given to these kindhearted androids. The protagonist, Da'at, a recently activated android, wakes up in the lunar base "Garden" and takes up their duty. This story is about a kindhearted android as they form a connection with the Ghosts. A tale following the sound of a bell secretly signaling the end of the world.