Two friends (Paola Senatore and Marina Hedman) compete sexually to win a man. Both are madly in love with him. La sfida erotica is a film made by assembling edited and unedited footage from other films. It begins with the two actresses soaking in the bathtub, each in her own home. They are preparing for the challenge, washing and caressing each other. After the bath, the challenge begins, and we witness a sex scene with Marina Hedman. First a blowjob, then she on top of him, then he on top of her. After this lengthy fuck, alternating with a performance by Paola Senatore taken entirely from the film Non stop sempre buio in sala, we discover other rules of the challenge: each of the two women must form a team and fuck until they are exhausted. A moment later we witness an orgy. The actresses involved are Cecilia Paloma, Herito Leine (credited as Joselita), Marina Hedman, and Marisa Costa. Herito Leine is fucking a man. Marisa Costa performs oral sex on Cecilia Paloma. Marina Hedman gives a blowjob to a guy. A strange thriller soundtrack plays in the background.
After a brief conversational interlude between Marina and Herito, the sex starts again. Marina is lying on a bed and a man is licking between her thighs, while Herito is sucking three cocks simultaneously. Soon after, Marina reciprocates and gives the man a blowjob. In the following scene, Paola Senatore is sitting on an armchair and masturbating thinking about a love encounter. The following hard sequence is from Non stop sempre buio in sala, but maybe there are some unreleased seconds. Meanwhile, Marina Hedman has sex on a lawn with a man. With twenty minutes to the end, Paola quits the challenge, with no explanation. To celebrate, Marina lies in bed and masturbates.
