Nerissa appears disguised as a student at Sheffield, but is soon uncovered and a battle ensues. The girls win by switching their enemies, knowing that element against element will only make them lose as the former Guardians have stronger powers and are more experienced. Hay Lin begins to wear braces on her teeth.

Lillian is actually the Heart of Earth, its source of magic, and the Guardians have to protect her. Cornelia attempts to gain her sister's trust. Matt, Mr. Huggles, and Napoleon become the Regents of Earth. Cornelia is forced to babysit her sister while her parents are out for the night.

Will makes a deal with Prince Phobos, since only the heir to the Meridian throne can claim its Heart. Seeing as it has become part of Nerissa's power source, in exchange for freedom he is obliged to return the Heart. Will is having a rampage on Mandy at the swimming competition.