Chum plot recap, spoiler-light
Newlyweds Tina and Tom travel to Malta for their destination wedding, accompanied by tensions stemming from unaddressed secrets and Tom's dismissiveness toward Tina's severe ocean phobia. Eager to ease the friction, Tom's enthusiastic best man, Rick, arranges a post-wedding excursion on a private catamaran in the Mediterranean Sea. The party includes Tina, Tom, Rick, close friends Rachinda and Brittany, and Tina's cynical younger sister, Sadie, alongside local skipper Captain Daniels.
Shortly after they sail far from shore, a massive great white shark aggressively rams the vessel, severely injuring Captain Daniels and compromising the hull. As the catamaran takes on water and the radio fails, the stranded wedding party panics while the apex predator circles the wreckage. Soon, a rugged fisherman named Roy approaches in his own boat.
The relieved survivors climb aboard his vessel, unaware that Roy harbors a sinister agenda. Roy turns out to be a grief-stricken widower obsessed with the exact shark that killed his wife years prior during their own wedding celebration, setting the stage for a horrifying ordeal.
