Los desafíos presents three separate stories that are linked by an American presence in Spain in the 1960s, with Dean Selmier playing the role of the American male in all three.
| Actor | Role |
|---|---|
 Dean SelmierBill/Allan/Charley | Bill/Allan/Charley |
 Francisco RabalCarlos | Carlos |
 Daisy GranadosFloricita | Floricita |
 Asunción BalaguerFernanda | Fernanda |
 Teresa RabalCuqui | Cuqui |
 Alfredo MayoGermán | Germán |
 Julia Gutiérrez CabaLola | Lola |
| BBarbara DeistBonnie | Bonnie |
 Fernando Sánchez PolackBenito | Benito |
| LLuis SuárezJulián | Julián |
| JJulia PeñaMaría | María |