Special Adventures are time-limited quests that offer unique prizes upon completion. Each Adventure has certain conditions to unlock (reach a specific Chapter/Year; complete another quest; etc), and will be added to your quest queue once unlocked. These Adventures will start one by one, with a 24-hour cooldown between quests.

To begin an available Special Adventure, select it from your Side Quests tab (scroll icon under your character portrait) and click on "Go" to be taken to your current objective. Adventures usually consist of multiple parts, each part divided into several tasks. Complete all tasks within the allotted time (quest timer displayed next to Adventure's name) to earn unique rewards, including outfits, tappable trophies, and even new friends.

Need more time to complete your quest?
Extend your Adventure by tapping on the clock icon on the Adventure page: use 55 gems or an add-time toffee to extend quest by 3 hours or watch a video ad to extend it by 20 minutes.
 

Need another chance to finish your quest?
Restart your Adventure via the Memory Book by using Pages. Some missed quests are available in the "Adventures" tab of the Book immidiately, while other Adventures will be added there with future updates to the game.
Beware, Quidditch Adventures cannot be replayed and therefore won't be added to the Memory Book. You get only one chance to complete your Quidditch quests!
   
TIP: If you have multiple Adventures in your quest queue that you would like to complete quickly, consider pausing main storyline progression while you wait for them to trigger. This is because the further your progress through the main storyline, the more Adventures get unlocked and added to your quest queue, increasing your backlog of available quests.