After a sudden family tragedy Cassie Blake moves to the town in which her mother had left years before that of Chance Harbor, Washington to live with her Grandmother. Soon she starts to learn from her new classmates things about her heritage that she never knew most importantly that they are all witches and that they want her to join them to create a new generation the Secret Circle.
Cassie befriends Sally Matthews, a non-witch, in attempt to distance herself from the Circle and build a normal life in Chance Harbor. Diana, worried that their powers are getting out of control, encourages everyone to bind the circle. However, Faye is enjoying the increased powers and refuses to participate, and Melissa flirts with Nick despite Faye's warnings.
Cassie receives an invitation to the school dance from a cute athlete named Luke, and she decides to accept his offer after seeing Adam and Diana spend time together at the boathouse. Melissa sees the dance as an chance to form a closer relationship with Nick.
Cassie looks up Heather Barnes, an old friend of her mother's, but is disappointed to learn that Heather has been in a catatonic state since the night of the fire 16 years ago. Feeling guilty that her mother and the Circle may be partially responsible for Heather's current state, Cassie tells Diana that she wants to use magic to help Heather.
Torn between her loyalties to the Circle and her family, Cassie wrestles with the secrets she must keep from her grandmother. Nick is thrown for a loop when Melissa adopts a new attitude and enlists his help to track down her family's Book of Shadows.
When Jake, a mysterious young man, shows up in Chance Harbor, he learns a lot has changed since his last visit. For one, the girl he left behind, Faye has discovered she's a witch and has plans to get even with the handsome guy who broke her heart. To complicate things further, he sets his sights on the alluring Cassie, much to Adam and Faye's dismay.
Deciding the Circle needs to have a little fun, Faye convinces Cassie to throw a big Halloween party. Intent on wooing Jake back, Faye goes all out on her Halloween costume. After a fight with Diana, Adam turns to Cassie for advice. Meanwhile, some dangerous, uninvited guests set their sights on the Circle.
After not hearing from her grandmother for a couple of days, Cassie becomes concerned and wants to go look for her. Diana decides the entire Circle should go in case Jane is in trouble. She also invites Jake along, much to Adam's dismay.
Cassie and Jake look into her father's side of the family, hoping to discover more about her lineage and why she has powers separate from the Circle. Meanwhile, Adam becomes protective of Cassie when Faye reveals that Jake might be hiding something dangerous from them.
Cassie turns to Adam when she uncovers a secret about herself that she needs kept from the rest of the Circle, including Diana. Meanwhile, Diana is thrilled when her grandmother Kate drops in for a visit, but Charles is suspicious of his mother's motives after Kate takes an unusual interest in Cassie.
Cassie asks Adam for help when she wants to look into her father's past, and their search leads them to an eerily familiar place. It also rekindles an old flame when Adam, thrilled to be spending time with Cassie again, asks her to the Fire and Ice dance.
Jake returns to Chance Harbor to warn Cassie that unless they find out how her father was killed in the boat fire sixteen years ago, she will endure the same death. Jake suggests an extremely dangerous plan to discover the truth about that fateful day, but Adam and Diana suspect he has ulterior motives.
Cassie enlists the Circle\'s help when she receives a frightening warning about the witch hunters\' return. At the same time, her true feelings for Adam and Jake surface during a birthday party that Ethan decides to throw with the help of Diana.
In honor of the holiday, Faye and Melissa throw a girls only anti-Valentine\'s Day slumber party for themselves and fellow witches Diana and Cassie. But the night gets wilder than expected when Melissa offers Diana some mood altering \"Devil\'s Spirit\" and the first person Diana loosens up around is Lee, who crashes the party to help Faye achieve her own power.
Cassie is stunned when a notoriously evil figure from her past shows up on her doorstep. However, her surprise quickly turns to suspicion when he asks her to return the medallion she found in the wreckage of the fire that killed their parents. Cassie storms off but is captured by Eben and his band of witch hunters.
Cassie catches Blackwell sneaking around the abandoned house. After confiding in Adam, he tells her he knows Blackwell was looking for a device to drain witches' powers and clearly back to his old ways. Faye shows up at Lee's house to invite him to the school fundraiser, but is taken aback when Eva greets her at the door claiming to be Lee's girlfriend. Meanwhile, Melissa encourages Diana to date a normal guy and points her in the direction of a new, handsome guy in town. Dawn runs into Blackwell at the school but the reunion isn't quite what she expected.
Blackwell warns Cassie and Adam that their love may be destiny, but it's also a curse. He suggests they go visit her grandmother, Jane to find out if there is a spell to reverse it. Jane warns Cassie that someone in the Circle will die if the curse is awakened. Meanwhile, Eva starts stalking Faye and Charles makes his next move against Blackwell.
Jake gets a surprise visit from an old acquaintance named Samuel, a witch hunter, who has a message for Blackwell about Eben\'s surprising next move. Cassie intervenes, forces Samuel to reveal his news and is stunned to find out what Eben is trying to resurrect. Meanwhile, Diana is frustrated that keeping the secrets of who they are is building a barrier between her and Grant. Faye and Melissa agree to help out Adam at the Boathouse and in return get him to help them use their magic to enhance their love life.
To protect themselves from the witch hunters, Jake, Cassie and Faye seek out Jake's grandfather Royce, to find his family's crystal and are confronted with disturbing theories about the events of sixteen years ago. Meanwhile, Diana tries to balance her pursuit of the Glaser crystal with Melissa and Adam with her romantic life with Grant, who demands to know what she's hiding. At the same time, Callum attempts to re-insert himself into Melissa's life. Charles and Jane plot their move against Blackwell.
When a crystal is magically stolen from the abandoned house, the Circle decides it was the traitor witch working with Eben so Jake calls for a meeting with Isaac to see if they can get him to change sides. Cassie's loose grasp on her dark magic threatens to destroy any possible alliance when their pursuit of the traitor leads them to the "Creepiest Place on Earth." Meanwhile, Faye and Jake work together to steal Dawn's crystal, Melissa and Adam pair up and uncover a new magic trick. Meanwhile, a frustrated Diana reaches out to Charles for help.
It's Prom night in Chance Harbor and after Adam uncloaks a crystal hidden in the school, Blackwell tells Cassie she can use her dark magic to find it. When Cassie follows this advice, it leads her to a dangerous discovery. Meanwhile, Faye invites Jake to Prom, despite the fact that he stood her up two years earlier. Adam, Diana, Cassie and Melissa finally make it to Prom but when they lose the crystal to Eben, they end up in a life and death situation. Meanwhile, Dawn attempts to stop Blackwell, who casts a deadly spell on Charles.
After Faye is attacked by the Witch Hunters, Jake, Melissa and Adam set out to save her. Blackwell tells Cassie and Diana that the only way to stop the Witch Hunters is to use their Balcoin blood to unleash the Crystal Skull. Diana is reluctant, but Cassie convinces her it's the only way to help their friend, but she'll need to tap into her dark magic to do it. Meanwhile, Dawn and Charles are faced with a new way to get their power back - but at a very big cost.