Walter lives near the top floor of a tall apartment building, where one night his habit of jumping on his bed leads to a tumultous fall through floor after floor, collecting occupants all the way down.

Moving into an apartment when his father loses his job, Georges befriends Safer, a twelve-year-old coffee-drinking loner and self-appointed spy, who recruits Georges into the world of espionage so that they can investigate a mysterious neighbor who liveson the top floor.

The upward progress of a rocket, lit in the basement by the janitor's son, causes some strange situations as it passes through twenty floors of apartments. "Iv̀n enciende un cohete en el s̤tano que rompe el techo y atraviesa cada piso, dejando un reguero de desastres y un agujero en cada p̀gina." --From publisher's description.