Producers: Troy Lum, Andrew Mason, Pete Shilaimon, Mickey Liddell, Brian Kavanaugh-Jones and Chris Ferguson   Director: Sean Byrne   Screenplay: Nick Lepard   Cast: Jai Courtney, Hassie Harrison, Josh Heuston, Rob Carlton, Ella Newton and Liam Greinke   Distributor: IFC Films/Shudder

Grade: C

If there were an Australian version of “Criminal Minds,” Sean Byrne’s thriller could, with just a bit of tweaking (portraying the cops as something other than the dimmest of bulbs, for instance), be an episode of it—longer (and grosser) than the norm, but otherwise fitting the mold.

The “unsub” is Bruce Tucker (a wildly over-the-top Jai Courtney), a guy suffering from wounds both physical and psychological as a result of being attacked by a shark as a kid.  He’s now the operator of a boat based at the Queensland coastal city of The Gold Coast (GC), on which he offers tours of the ocean that specialize in shark-cage trips beneath the surface for guests to experience first-hand the thrill of seeing the creatures up close and personal. 

But, as a prologue in which tourist couple Heather (Ella Newton) and Greg (Liam Greinke) take him up on the scary proposition shows, Tucker has something more gruesome in mind.  He is, as will shortly be revealed, a serial killer who films folks in their death throes as he hoists them above the water and slowly dunks them into the waves as shark food.  He has a cabinet stocked with the videos, each with a lock of the victim’s hair attached. 

Enter Zephyr (Hassie Harrison), an uninhibited surfer who lives out of her van as she seeks out new beaches.  She’s approached outside a store by clean-cut Moses Markley (Josh Heuston) for a jump-start on his car battery; the two spark as well and spend the night together.  In the morning she’s off, leaving him pining after the girl who might just be the one.  He determines to track her down. 

But Zephyr’s been kidnapped from a beachfront parking lot by Tucker and taken to his boat, where he chains her in a hold beside the terrified Heather.  It’s not long before the latter will meet the grisly fate Tucker’s meted out to so many as Zephyr’s forced to watch.

Meanwhile Moses, who’s sought out police help to no avail, manages to find Zephyr’s surfboard on the beach and uses security footage from the parking lot where Zephyr’s van was abandoned to identify Tucker’s truck and locate his boat.  His rescue attempt, however, is foiled by Dave (Rob Carlton), Tucker’s zonked-out dock neighbor, though in the process Carlton plays the Scatman Crothers “Shining” role of the guy whose intervention proves a fatal miscalculation.

Now Moses has joined Zephyr in captivity, and Tucker has evil plans for them both.  From this point the movie becomes an over-extended cat-and-mouse game as ever-feisty Zephyr and meek but devoted Moses try to avoid getting fed to the sharks and escape wild-eyed Tucker’s clutches.  The presence of a loud party encampment not far from where the boat’s dropped anchor offers some hope of outside help, but attempts to attract the revelers’ attention prove unavailing.  Still, Zephyr is indefatigable even after Moses, whom she gets more and more devoted to, is seriously injured while being forced to literally swim with the sharks. 

This is very silly stuff, but it’s executed with a grim efficiency that will put it over with viewers who are entertained by what amount to a series of extended exercises in sadism. (Kasra Rassoulzadegan’s editing drags every morbid bit of business out as long as possible.) Byrne and his crew—production designer Pete Baxter, costumer Marion Boyce and cinematographer Shelly Farthing-Dawe—do a good job of creating the claustrophobic feel of Tucker’s grubby boat, while David White’s sound design and Michael Yezerski’s score accentuate the sinister vibe.

And the cast certainly get into the swing of things.  Courtney chews up the scenery with glee, while Harrison demonstrates endless reservoirs of pluck and Newton equally deep ones of nervous fear.  Heuston makes an amiably self-deprecating would-be hero, but Carlton’s goofy neighbor rivals Courtney in excess.

As to the sharks, they’re pretty much standard-issue effects (the VFX supervisor was Andrew Mason), acceptable enough until the script calls for a mega-shark for the wacked-out finale, which comes off looking pretty phony.  But it does make for a properly extravagant sendoff for Tucker, who goes out like a bargain-basement Quint in an obvious tip of the hat to “Jaws.”