Haven Town is facing total annihilation at the hands (and teeth) of a horde of monsters from beyond the Shadowrift.
You, the heroes, must band together to drive them back. To do this, you will need powerful spells, skills, attacks and loot. When the game begins, you are a basic hero; you can explore and fight. Luckily for you, Shadowrift is a deck-building game! You can buy new cards to add to your deck, cards that will define you as an adventurer and complement the strengths of your fellow heroes. Unlike other deck-builders, there is constant interaction with your fellow players as you figure out who will gain which benefit from the limited supply of townsfolk, offer their coin to help construct walls, and seek healing from anyone who's learned such magic.
Shadowrift also features monsters that don't merely sit waiting to be slain; if you leave them alone, they will rip Haven Town asunder. They'll kill people, break walls, and kick your heroes in the face. Combat with them is intuitive (though frequently painful). For defeating a monster, heroes gain Heroism, a simple, consistent boost to their power that makes them better at anything they undertake. Since the monsters won't stop coming until the last Shadowrift is sealed or the town has been built into a mighty fortress, you'll need every boost you can take.
The second edition of Shadowrift features many improved mechanisms, including a revised system for how monsters choose who to attack (based on types of villagers, instead of specific people) and a new system for monster powers (making them much more dangerous). It also has a revised card layout and a great deal of new and improved artwork.