Milan, 22 December 1928. The Baldassini family with their friend Sirio at the Porta Venezia Gardens. We see Sirio, Laura, the wife of cinematographer Guglielmo Baldassini who is filming in 9.5 mm, and their children Luciano and Marisa walking towards the camera along the park paths. Then the camera passes into Sirio's hands: in the group portrait there is now Guglielmo, holding and twirling a stick in imitation of the Charlot. This is followed by close-ups of the individuals and when it is Guglielmo's turn an inexplicable phenomenon happens: the smoke from the cigarette he is smoking enters his mouth instead of coming out. It is a special cinematic effect obtained by shooting in reverse, one of those tricks that originally decreed the success of the invention of cinema, a new device to document reality and overturn it, a revolutionary power to challenge the impossible. The effect in projection will be magical: children will like it, everyone will like it. Guglielmo will condense the contents of the reel with an inscription above the box: “At the gardens - Us - Sirio - portraits - me upside down”.