The first two minutes of “Your Sister’s Sister” are somewhat generic. A few friends have gathered (drinks in hand) to celebrate the short life of their friend Tom. As those he left behind share stories from his life, his brother, Jack (Mark Duplass) is eager to interrupt. From then on, the film proves to be unlike most. The naturally spoken dialogue is witty, compelling, and stunningly realistic.

Jack decides that he doesn’t want to comply with the inflated practices of a memorial party. He makes it known that his brother was a flawed human being. He implores them to “honor the man” rather than the glorified persona that was fabricated after his demise. His outburst is muffled by Iris (Emily Blunt), his brother’s ex-girlfriend. Iris brusquely informs him that he is in dire need of a retreat from his sullen existence. On his last leg emotionally, Jack is in no position to ignore her suggestion that he stay at her family’s isolated cabin.

His plan to shun human interaction and reflect on personal matters is disrupted when he learns that Iris’s sister Hannah (Rosmarie DeWitt) is staying there as well. Once the initial shock that they are housemates subsides, the two enjoy and evening of drinking and candid discussions. Reeling from the end of a seven-year relationship, Hannah is allayed by Jack’s presence and quickly takes their interaction a step further. When Iris shows up unexpectedly the next morning, it sets off a string of emotional revelations.

Largely improvised, the story’s premise was Duplass’s creation. With the aid of director Lynn Shelton, the story was further developed by all three lead actors. The result is a seemingly effortless depiction of love, pain, and longing. Brilliantly acted, poignant, and thoroughly enjoyable, “Your Sister’s Sister” is a rare indie gem that is bound to be one of the highlights of the Tribeca Film Festival.