Gwen has her first encounter with Morgana when Merlin's nemesis kidnaps Tasha in an effort to force Gwen to help her secure the ultimate prize: Merlin's Stone, an ancient crystal that holds the key to immortality. The rift between Gwen and Josh begins to mend as the two unite to save Tasha - and defeat Morgana. Merlin endows Gwen with a special gift: a talisman that belonged to Guinevere, and which will help Gwen to focus her power.

As the high school prepares a production of MacBeth, Gwen runs afoul of Wind, Reine and Fire when queen bee Reine realizes Gwen is her chief competition for Josh's affections. Meanwhile, Katie follows Gwen to the forest glade and discovers the secret of Gwen's magic - only to become the object of derision when she tries to impress the disbelieving kids at school with the knowledge. Patrick O'Leary takes up a teaching position at Griffin High.