OK, if you are a fan of Mystery Science Theater 3000 and love to mock movies, then you will have a lot of fun with this. Otherwise, it may really be TOO painful to see.
Plot: Obsessed cryptozoologist sneaks a huge crate containing a Chupacabra onto a cruise ship (apparently not having to declare it at customs, or even mention that he's bringing aboard a live animal -"no really, it's research equipment, the air holes are just an accident"). Some dipsticks he hired to lade it open the crate, figuring he paid bunches of money, maybe there's something to steal. Once the WOOD CRATE is open, the Chupacabra breaks through the STEEL BARS inside and goes on a killing rampage.
Yeah, whatever.
By a stroke of sheer coincidence, a Marshall (I assume a U.S. Marshall, since he was in the gulf war, not just some guy named Marshall) is on board, investigating some money that went missing from the ship's safe. He's posing as an insurance salesman ("Lady, I'm the best insurance you've got..."). Other scintillating characters include the captain (John Rhys-Davies, and sadly his dignity is the first victim of the film), his tae-bo instructor daughter (snicker - Tae-bo), an annoying old stuck-up lady with a tiny dog which should be fed to a cat (guess WHAT eats it...?) and an incredibly unpleasant gigolo who might have been believable in a movie made in 1964, not in anything more recent. Much of the acting was really bad, and the characters were just there so that you can laugh hysterically when they died.
Overall - SCREAMINGLY bad. Bad on many levels. BAD BAD BAD. What??? Bullets don't even make Chupacabra flinch, but the Tae-bo bimbo can punch him and scare him away???? Hey Sci-fi Channel, you desperate for scripts or what?