A boarding house located in the crumbling building of a former school has sheltered many strange people. The owner is an eccentric writer obsessed with the metro and dreaming of visiting every subway system in the world. A young violinist who ran away from her family and newborn daughter—and her new friend, a flutist, with whom she now plays in the underground passages. A boy, forgotten by his carefree mother, skips school to ride the roofs of subway cars like a real extreme sportsman. A peculiar braid of fates, tangled as if like lines of a metro map, leads each person to their own tragedy—and all together to a dramatic resolution...