During the beginning of the series Sakura is 10 years old and living in the town of Tomoeda, located in Japan. One day in early April Sakura stumbles across a mysterious book called The Clow in her fathers study. As soon as the touched the book Sakura awakens one of the card guardians,Cerberus. He was sleeping on the cover protecting the Clow Cards, a deck of 19 cards with incredible powers. After he emerged from the book Cerberus admits that he let the cards slip away as he slept. Realizing Sakura's magical powers, Cerberus tricks her into becoming the “Cardcaptor”. This bounds her to the duty of collecting the cards and returning them to the book. Later on in the series it is discovered that Cerberus was marking Sakura as the one and only candidate to become the next master of the Clow cards, and their guardians.