Aardvark is a hard movie to pin down, but it's safe to say it isn't about aardvarks.

The offbeat, off-putting film stars Zachary Quinto as Josh, a man with significant mental health issues, who has just started seeing therapist Emily (Jenny Slate), newly established in the small university town where she studied.

Josh is not very stable, and Emily is not very good at her job. This could be the catalyst for dramatic tension, but there is little of that at the outset of Aardvark, full of awkwardly scripted exchanges between therapist and patient that cause us to wonder if the movie is aware of how dangerously inept she is.

Her actions (she's entirely unconcerned about the source of her patient's powerful medication) are so hard to believe, in fact, we wonder if she actually exists. This is also a function of the shifty way writer-director Brian Shoaf presents the material.

Josh, you see, is prone to delusions. His latest crisis has been brought on by the return of his brother Craig (Jon Hamm), which both pleases and provokes Josh, who admires his famous actor brother and also feels abandoned by him. Josh's obsession warps his perception of reality: He believes the shape-shifting Craig is "playing" the people he meets on the street, or in the coffee shop where he works.

Craig may even have taken the form of the pretty woman named Hannah (Sheila Vand) who has started taking evening walks with Josh – a situation so improbable as to invite the interpretation that it is a delusion. Shoaf seems deliberately coy about it – there are only half a dozen characters in the film, and he's careful to compose scenes so that Josh interacts with each character individually, inviting speculation that they may be figments of his imagination. (It doesn't help Aardvark that it's been so recently preceded by Entanglement, a movie that offered a remarkably similar scenario.)

It's not until Josh, Emily, and Craig finally interact that we're convinced they're real, and Hannah's existence isn't resolved until the final scene.

This all gets a bit grating, even at 85 minutes. In its last moments, though, Aardvark finds a groove. Josh's illness deepens and becomes more severe, leading to a scene wherein Quinto and Hamm (ill-used to this point) manage to sketch, in just a few minutes, a lifetime of brotherly misunderstanding.

We sense Craig's guilt, Josh's bewilderment, and the passage of time that has suddenly left the two of them at a point where reconciliation, and forgiveness, are possible. It's a long wait, though, and until that time, expect Aardvark to make you antsy.