The original Overcooked is a party game based around working together to navigate the chaos of the kitchen while somehow producing good food quickly. Overcooked 2 is very much the same in that regard, its just turning up the culinary mayhem up a couple more notches.
The basic setup of Overcooked 2 is that the Onion King didnt learn his lesson from the first game, and hes once again inadvertently created a potentially apocalyptic situation by reading from the Necro-nom-nomicon. Theres no time to lose and lots of orders to fill, so its up to the the players team of top-notch chefs to cook their way through all of the Onion Kingdoms improbable kitchens and save the hungry hordes.
Source: N4G PC Overcooked 2s Recipe Calls for an Extra Dollop of Chaos | Hardcore Gamer