This is the third in the line of films about a zed type virus being unleashed. The first two were contained within an apartment building but in this one, it has gotten out and made its way to a couples’ happiest day…. Well, it was supposed to be anyway. They instead end up hacking up a majority of their guests and have to contend with a blood-thirsty horde. With some twists and turns it ties together the first two films and sets up the future 4th and final movie.