“Expiration” is a student film of enormous ambition and modest attainment. Though movies are necessarily a collaborative medium, it’s essentially the work of Gavin Heffernan, a young Canadian who not only wrote, directed and edited it but serves as the male lead, too. Heffernan exhibits some talent–more in some of these capacities than in others–but it’s arguable that in this case he’s spread himself too thin. After all, even Orson Welles depended heavily on many others when he made “Citizen Kane.”

The film is very fragmentary in structure, but essentially it’s about three young characters who learn about themselves, and reach decisions about difficult dilemmas in their lives, during encounters over an eventful night (and early morning) in Montreal. One is Rachel (Janet Lane), a self-controlled local girl who makes drug deliveries for a scruffy dealer. Another is Julia (Erin Simkin), who’s pregnant. And the third–the one who links the other two–is Sam (Heffernan), the childhood pal who may or may not be the father of Julia’s child but, as a good guy, is intending to propose to her one way or the other. But he leaves his intended sleeping alone in their car during That Night in Montreal after she’s gotten sick on dinner (he slips off to get her some medicine, I think), and he’s thrown together with Rachel when they’re both robbed in a convenience store heist; he joins Rachel to track down the robber and recover their (extremely important) property. While the now-abandoned (and awake) Julia links up with a prostitute (Denise DePass) who introduces her to a daughter (Yetide Badaki) from whom she learns something about the problems faced by accidental children, Sam and Rachel go through a series of strange adventures to find the thief (Laen Hershler) and retrieve his mother’s ring (which he intends to give to Julia) and the parcel of drugs she has to deliver to a high-paying customer before 5am or suffer dire consequences. All the main characters come together at the pad of the drug buyer, a highly agitated fellow named Jeremy (Paul Rogic) who plans a major event at dawn. Jeremy’s decision leads them to choices of their own.

“Expiration” tries to grapple with issues of free will and fate and the ties that link the past to present and future, but it does so in a fashion entirely too reminiscent of film school exercises: the style is arty and fractured, constantly calling attention to itself with frequent cutaways, inserts and flashbacks. One gets the feeling that the various episodes were devised in isolation, for their individual effect, and then tossed together with lots of smoke and mirrors in the hope that they’d form a unified argument of some sort. The result is that “Expiration” alternates between moments of imagination, insight and curious beauty and others that come across as amateurish, silly and clumsily realized. The acting is highly variable as well, with Heffernan awfully subdued and fidgety (perhaps looking as tired and flustered as he does because of the pressure of all his other obligations) and Simkin a bit too broad, maybe to balance things. Of the leads Lane comes off best, simply because her controlled performance seems the most mature. Among the supporting cast, some–like DePass as the world-wise hooker–are quite good, while others–like Hershler and Rogic–are far too aggressive. (Another Heffernan–Gavin’s mom–appears as Sam’s mother. It’s a pleasant show of maternal support.) The camera work is also hit-and-miss, boasting quite a few elegant compositions but including many crude, obviously on-the-fly sequences. Similarly, John Day’s music is only periodically effective.

“Expiration” is the sort of picture you might want to take a look at years from now, when the participants may have gone on to better things, to discern the signs of their potential in their early work. On its own, however, it resembles the lesser items you’re likely to encounter (or more likely skip) in one of the smaller film festivals–precocious, perhaps, but also uncomfortably pretentious. One must admit, however, that at least it tries, even if its reach exceeds its grasp.

In its DVD incarnation, incidentally, “Expiration” comes complete with an audio commentary by–you guessed it–Gavin Heffernan. He definitely overuses the word “cool,” but then he’s only twenty-three, a couple of years younger than Welles was when he made “Kane.” This debut may be more promising than successful, but he’s got plenty of time to do better.