Contingency Contract (CC) is Arknights' most challenging endgame content. It's a rotating event that features a set of permanent and seasonal stages, each with a list of 'Contracts' (debuffs to your operators or buffs to enemies) that you can activate to increase the difficulty and earn 'Contract Bounties'. These bounties are exchanged for exclusive rewards, including operator skins, materials, and even 6-star operators.
CC requires deep understanding of game mechanics, strong operator rosters, and precise strategy. It's not content for new players, but something to aspire to. The 'Permanent Site' allows you to practice and clear contracts at your own pace, while 'Daily Stages' offer new challenges each day. Don't be discouraged if you can't clear high-risk contracts initially; even clearing lower risks provides valuable rewards. Focus on understanding enemy routes and operator synergies.