One of the special things about families is how well the members of the family unit know each other. Beyond all the personality affectations and false protestations, the true self is always readily identifiable by the people one spent most time with during the formative years. Those people would be mothers, fathers, brothers and/or sisters, and they are seemingly inescapable. Union Square is all about family, showcasing all of the awful things that come packaged with relatives, while reminding of all the good aspects people take for granted.

Lucy (Mira Sorvino) is in the middle of a midlife crisis. She’s traveled from the Bronx to surprise her lover – a married man – and rather than enjoy a night of debauchery, he ends their relationship. Distraught over being rejected, Lucy visits the person she knows best who’s closest in proximity, her sister Jenny (Tammy Blanchard). Unfortunately, the two haven’t spoken in three years, and Jenny seems to be the opposite of Lucy. Jenny has her life together. She’s about to marry a handsome, responsible guy named Bill (Mike Doyle), who she runs a small business with. They have a lovely apartment off Union Square, and this life seems to suit Jenny well. However, when Lucy invites herself to spend the night, Jenny’s perfect life takes unexpected turns that threaten to unravel everything she’s built.

In a very big way, Union Square plays on the always reliable “guest-who-won’t-leave” plot where the guest is usually frustratingly annoying while the reserved host goes nuts coping. In this case, Mira Sorvino is the guest, and she is frustratingly annoying. She’s the kind of person who has loud, obnoxious phone calls in public, can’t make up her mind on what to text someone, and has no regard for other people’s property or privacy. What makes her performance exceedingly effective is that audiences will probably know someone just like her in their real lives – perhaps not exactly like her – but close enough to sympathize with the people who must host Lucy. To that end, Sorvino handles her role well, riding the line of credibility without going over.

If the film were only about being annoying it would be a failure. Fortunately, just when the audience has grown sick of Lucy and desperately wants Jenny to throw her out, Union Square adds another dimension to both sisters, evening out sympathies between the two. Credit goes to both writer/director Nancy Savoca and writer Mary Tobler for their excellent handling of this change by use of simple, natural dialogue and settings. There’s a kind of unguarded equilibrium that siblings settle in after enough time, and that portrayal is recreated onscreen with enjoyable realism.

With that in mind, it’s hard to know how many people this film will resonate with. While the movie feels natural, it also reminds of watching someone else’s family home videos. There’s no real investment in the characters. Lucy’s behavior is so off-putting and erratic that it’s hard to care about her situation. Likewise, audiences don’t know enough about Jenny to really root for her either. Sadly, there’s also no real sense that the characters are working towards achieving anything. That leaves audiences just experiencing a snippet of other people’s lives until the credits roll.

Surprisingly, there is a catharsis to be had here. There is realization. There is understanding. And there are many real life truths that Union Square will point out. This is the kind of movie that most people will probably never watch twice, but the film makes a good argument for watching it at least once.