Shugo Chara! Vol 5

From the Kodansha edition

THE NEW KIDS! Amu and her Guardian Characters have found a home at an elite school. But now two new Guardians have been chosen, and each has a secret. One is more complex than Amu thought, and the other may be out to betray the Guardians to the evil Easter Corporation! This volume of Shugo Chara! includes special extras after the story!

Source: Penguin Random House API