Song of the Wanderer: The Unicorn Chronicles, Book Two by Bruce Coville is a book about Cara Hunter and her journey back to Earth from Luster to fetch her grandmother, Ivy Morris. Along the way, Cara learns about her family's mysterious history and their involvement with unicorns. Upon returning to Earth, Cara is confronted by her ancestor, Beloved, who seeks to destroy the unicorns and any world they inhabit. In the end Cara learns about herself, her family, and both the unicorns and the world they now inhabit: Luster.

The book begins where the first one, Into the Land of the Unicorns, left off. Cara is in the Queen's court in Luster. The Queen, Arabella Skydancer, tells Cara that she needs to return to earth and find her grandmother, Ivy Morris, who is known to the Unicorns as "The Wanderer." To help Cara with her task, the unicorns Moonheart, Belle, and Finder go with her on her quest to retrieve her grandmother. She is to return to earth using the amulet her grandmother gave her which allows her to travel between Earth and Luster. Cara's human friend, Thomas the Tinker, joins up with them in a few days. They arrive at the cave of M'Gama, The Geomancer, who leads Cara underground and performs a spell to find out which gate Cara needs to use in order to return to earth and find her grandmother. The gate is in the cave of the seventh dragon, Ebillan. M'Gama then gives Cara a green ring and a sword.

When they set out again on their travels, the group meets The Queen's Players. Among this group of humans is a man named Jacques, who was once married to Cara's grandmother. He decides to join Cara and her group on their quest. The gang is soon attacked by a group of delvers. Lightfoot and the Dimblethum charge out of the forest to save them. After the battle, the group meets up with Grimwald, keeper of the Unicorn Chronicles. He leads them on a shortcut underground and tells all of them the story of how Ivy Morris first came to Luster. Before sending the group back above ground, Grimwald gives Cara a big red jewel, which she looks into and briefly sees her mother.

Once above ground, Cara has a dream in which she is contacted by her diabolic ancestor and enemy to all unicorns, Beloved. Cara wakes in a fright and runs off into the woods where she happens upon a Gryphon. His name is Medafil and he is trapped. Cara frees him and he takes her to his nest, where he gives her a glowing sphere and a seashell. When she places the seashell to her ear, Cara hears her grandmother singing "The Song of the Wanderer." Medafil then returns her to the rest of the group and takes them to Ebilan's territory. Cara bargains with the dragon, eventually giving him the seashell in order for him to allow her to use the gate leading back to earth in his cave. Once in Ebilan's cave, Cara returns to earth, only to find Beloved waiting for her. Beloved wants Cara's amulet, in order to enter Luster. Lightfoot and Jacques then enter and fight with the Hunters Beloved brought with her. Cara's father, Ian Hunter is there and he ends up betraying Beloved in order to save his daughter. After Beloved and the rest of the Hunters flee, Cara finds her grandmother's body. Her grandmother is trapped in the Rainbow Prison and Cara sings "The Song of the Wanderer" and joins her there. The Queen of the Unicorns, Arabella Skydancer, also meets them there. She tells both Cara and Ivy that Ivy is actually a unicorn. Ivy is Amilia Flickerfoot, the queen's long-lost granddaughter and heir to the Unicorn throne.

After being released from the Rainbow Prison, Ivy, Cara, and most everyone else in their group return to the Queen's Court. Shortly after their arrival the Queen dies. M'Gama then breaks the Queen's horn over her knee. The magic released by the broken horn causes Ivy to turn back into her true form, that of the unicorn Amalia Flickerfoot. Amalia then takes her place as the rightful new queen of the unicorns.