One summer afternoon, on the banks of a river, a boy and a girl are starting to get to know each other. The landscape and the distance are the scene of a possible beginning.

Trombone is not a classic documentary, in the same way that Trombonanza is not a classic experience in the world of trombone. It is full of moving stories, secret tributes, huge celebrations and above all music.

Tomás is a teenager whose life, as always happens, changed from one moment to the next. But that present awakens a latent past that must be resolved in order to face the uncertain future.

Ariel is a middle-class young man, a father of a family, who surprisingly loses his job in the context of a wave of layoffs. Altered and hiding from his family what happened, he escapes his father-in-law's birthday to go to a nightclub, where an old acquaintance offers to be part of a narco business. Ariel accepts, trusting that his participation will be limited, but things go out of control.

The discovery of a mysterious letter turns the archaeological remains of Santa Fe La Vieja into a playground for adventure. The mission Mina's grandfather entrusts his granddaughter with will unravel a web of intrigue that will reveal stories of a city from bygone times. A city built on the shores of a freshwater sea that still has secrets to tell.