Four extraterrestrials, X-1, X-2, X-3 and X-4, arrive on Earth in the early sixties. Here they decide to take on human features to study the terrestrials incognito, but end up getting involved in the Roman "dolce vita".

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Main Cast: Paolo Panelli, Carlo Croccolo, Enzo Garinei, Alfredo Landa, Magali Noël, Ciccio Ingrassia, Franco Franchi, Pietro De Vico, Valeria Fabrizi, Nando Martellini

Directors: Pipolo, Franco Castellano

Writers: Franco Castellano, Pipolo

Editor: Gisa Radicchi Levi

Cinematographer: Alfio Contini

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