Il Filo is a play in verse, written for actors playing the roles of puppets. Il Filo was notably performed with Eleonora Duse in the role of Colombina, at the Teatro Carignano in Turin, in January 1883. The initial dedication is an acknowledgement to Arrigo Boito, who collaborated on the revision of the lines in the Venetian language. The first edition of Il Filo was published in 1883 and features several illustrations by Edoardo Calandra. In addition to those representing Eleonora Duse in various scenes, the edition also shows a representation of Giacosa pulling the strings of the puppets and, in the acknowledgment to Boito, the portrait of a young Arrigo in the act of writing, with the puppets of Alecchino and Pantalone guiding his hands.

The action takes place in the backstage of a puppet theatre, where the puppets are hung. To his companions’ disbelief, the Doctor claims that he has read in a book that puppets are carried by strings manipulated by men. Colombina proposes to show that men are also held by a string – a string that binds their heart. All the puppets tell a story about the meanness or the sadness of human life. Colombina concludes that, perhaps, the string is invisible to those who are held by it, and that, just like men, puppets do not realise what ties them. Her companions do not believe her, and while they lay out of their belief that they are autonomous, the puppeteers remove them one by one from the room where they were kept and makes them go on stage – the show is about to begin.