Pinín and his small group of friends discover that the river they frequent is being polluted, affecting all the animals and plants in the area. The group, along with an old captain struggling with alcoholism, will search for the cause of the problem in order to solve it.
| Actor | Role |
|---|---|
| MManuel de RiveroFino | Fino |
| AAdrián MieresPinín | Pinín |
 Rafael ArcosDueño fábrica | Dueño fábrica |
 Lola LemosBruja Dientes | Bruja Dientes |
 Carmen Martínez SierraBruja Bigotes | Bruja Bigotes |
| MMimí MuñozBruja Güestia | Bruja Güestia |
 Ricardo PalaciosCapitán Prendes | Capitán Prendes |
| LLuis G. IglesiasRufo | Rufo |
| CClara FerrerTelva | Telva |