The central conceit of "Perfect Strangers" is a game where seven friends agree to share all incoming calls and messages for one night. This decision systematically blows up their lives in a hypothetical timeline. The key revelations are:
- Cosimo's Infidelities: The newlywed Cosimo (Edoardo Leo) is cheating on his wife Bianca (Alba Rohrwacher). This escalates dramatically when it's revealed he is having an affair with Eva (Kasia Smutniak), the host and his friend's wife. The final blow comes when another mistress calls, revealing she might be pregnant, shattering Bianca.
- Peppe's Sexuality: Peppe (Giuseppe Battiston), who claimed his new girlfriend Lucilla was sick, is revealed to be gay. To protect his friend Lele from embarrassment over receiving racy photos, they swap phones. A tender message from a man named Lucio arrives on Peppe's phone (now in Lele's possession), outing Peppe to the group after much confusion. The subsequent homophobic reactions from some friends are stark and painful.
- Eva's Hypocrisy: Eva, a therapist, is revealed to be secretly planning a breast augmentation, a fact she hid from her plastic surgeon husband, Rocco (Marco Giallini). Her affair with Cosimo makes her a chief hypocrite, especially after she instigated the game.
- Carlotta and Lele's Marital strife: Carlotta (Anna Foglietta) has been sending provocative photos online and wants to put her mother-in-law in a nursing home against Lele's (Valerio Mastandrea) wishes. Lele is also having an online affair.
The film's most significant twist is its ending. After the dinner party from hell, the guests leave Rocco and Eva's apartment. As they walk out into the night, the lunar eclipse ends, and their interactions reveal that none of the explosive events actually happened. They are all still friends and couples, their secrets safely hidden. Cosimo and Bianca are happily in love, Peppe is still closeted to his friends, and Eva and Rocco's marriage is intact. This reveals that the entire film was a 'what-if' scenario, showing the catastrophic outcome had they actually played the game. The final scenes show them going home and immediately reverting to their secret lives—Lele checking the racy photos, Eva and Cosimo exchanging a knowing look—driving home the chilling point that this fragile peace is built entirely on deception.