At the start of the series, Sakura is 10 years old and living in a fictional town called Tomoeda in Japan. It is supposedly located not far from Tokyo. One day in early April, shortly after her birthday and only slightly into her fourth grade year at Tomoeda Elementary School (Reedington Middle School in Cardcaptors), young Sakura stumbles across a mysterious old book called The Clow in her father’s study. Instantly upon touching the book, a confused Sakura mistakenly awakens one of the card’s guardians, Keroberus who was sleeping on the front cover where he was supposed to be guarding the Clow Cards: a deck of 19 (52 in the anime) magical cards with incredible powers. Upon emerging from the book, Keroberus admits to having let the cards slip away as he slumbered, and, realizing Sakura’s magical potential, cunningly tricks her into becoming the "Cardcaptor" and duty bound to collect all of the missing cards and return them to the book where they will then be under her control.