THE WHORE AND THE WHALE (2004)

Nicolás, Pilar, Cata, Manuela, and Nacho have been friends since they were teenagers. At twenty-five, they're still close, although with more differences than common ground.

Nico suggests celebrating New Year's Eve at the family home in Tigre. Without consulting them, Manuela invites Belén, her childhood friend. The group's resistance is felt: Belén is superficial and vain. However, her dazzling physical charm makes the men accept her with less hesitation, and the initial rejection seems to be overcome.
Nicolás is a fervent follower of any theory that opposes monogamy. Love doesn't exist, and men are meant to satisfy their sexual desire with as many women as possible; the rest is social mandates, he says.
True to form, Nico seduces and spends the night with each of the girls. After spending time with Manuela—his best friend Nacho's girlfriend—he discovers he's in love. The feeling is overwhelming, and he doesn't hesitate to declare it.
The group enters a crisis. Amidst recriminations and open discussions, it becomes clear that Nicolás wasn't the only one who broke the rules of friendship.