The producers urged Antonioni to solve the Anna mystery.He never agreed and he was certainly right.It gives his work an aura of mystery ,something which we would find later in "Picnic at Hanging Rock" (both the novel and Peter Weir's movie).
The first part introduces the three main characters:Sandro,Claudia and Anna .Anna is a spoiled child who spends her time going on a cruise with a golden youth.It' s important to notice that her friend Claudia does not seem to come from such a wealthy family.Some critics also noticed that the relationship Anna/Claudia in their cabin was somewhat ambiguous.
The scenes on the tiny desert island are among the best in the Italian cinema.It was the right place for a mysterious disappearance: crime? suicide? accident? escape? It's all within the realms of possibility.
The second part is Sandro's and Claudia's investigation.Several Antonioni movies take the form of an investigation :from "cronaca di un amore" to "Blow-up" to " Professione :reporter".But little by little,the boy and the girl finally forget Anna and begin a difficult love affair.
Excellent use of a baroque palace,which,while being real ,foreshadows Alain Resnais's "Marienbad".