Ruby Red

The novel opens with a prologue set in Hyde Park, London, on April 8, 1912. An unnamed man and woman arrive via time travel. The woman weeps as the man wraps a chronograph, a device used to control time travel, in cloth. They have abandoned a girl they love for her safety and will never see her again. The man proposes marriage aboard the Titanic, planning to disembark in Ireland before the ship's doomed voyage continues. They agree that adversaries will track them down and that they may be the only ones who can stop a powerful figure from carrying out his plans.

Gwyneth Shepherd, a 16-year-old student at St. Lennox High School in London, lives with her extended family in a grand Mayfair townhouse. For years, the household has focused on her cousin Charlotte Montrose, who is expected to inherit a time-travel gene that runs through the family bloodline. Charlotte has spent her childhood preparing with fencing, dancing, riding, and language lessons. The family anxiously monitors her for dizzy spells, the sign that her first uncontrolled time-travel episode is imminent. Gwyneth possesses her own unusual ability: She can see and hear ghosts, a gift no one else in the family shares.

One day, Gwyneth experiences an alarming dizzy spell at school but dismisses it. When Charlotte reports dizziness during class, Gwyneth escorts her home, but Charlotte never vanishes. After they arrive, Gwyneth feels the dizziness again. Great-aunt Maddy, who experiences prophetic visions, shares key background: The de Villiers family carries the time-travel gene through its male line, and Gideon de Villiers has already been traveling for two years. Gwyneth's cousin Lucy Montrose ran away at 17 and was never heard from again. Charlotte's birth date was calculated centuries ago to identify the gene carrier. Gwyneth, born one day after Charlotte according to her birth certificate, privately suspects the calculations may be wrong. A driver takes Charlotte to the Temple, the headquarters of a secret society called the Lodge that oversees the time travelers.

Sent on an errand, Gwyneth travels back in time for the first time, landing on a subtly altered version of her street before snapping back to the present. She calls her best friend Lesley Hay, who urges her to tell her mother, but Gwyneth hesitates. That evening, she tries to confess to her mother Grace but loses her nerve when Grace suggests the family has "too much imagination." Overnight, the dizziness sends Gwyneth into the past inside the family home, where servants chase her before she returns. During another episode at school, she travels to a candlelit party in the building's past. Hiding behind a curtain, she sees a girl in a midnight-blue silk gown who has Gwyneth's face, including her distinctive crescent-shaped birthmark. The girl signals Gwyneth to hide, then kisses a young man to distract him from investigating. Gwyneth realizes the girl is her future self.

Gwyneth finally calls Grace, who reveals a devastating truth: Gwyneth was born on October 7, the same day as Charlotte, not the 8th as her birth certificate states. Grace and her late husband bribed the midwife to alter the date, wanting to spare Gwyneth the preparation Charlotte endured. Grace identifies Gwyneth as the Ruby, the 12th and final member of a group called the Circle of Twelve, in which each time traveler is represented by a gemstone.

At the Temple, Gwyneth and Grace confront the assembled Guardians, the Lodge's members who manage the time travelers. Those present include Falk de Villiers, the Grand Master, and Thomas George, a member of the senior leadership called the Inner Circle. Charlotte's mother, Aunt Glenda, accuses Grace of lying, referencing a past incident in which Grace helped Lucy and Paul de Villiers, Falk's brother and Lucy's partner, escape with a stolen chronograph. To confirm Gwyneth's abilities, Mr. George stations her in an underground room safe in any era. She travels and returns, proving her status. Gwyneth then meets Gideon de Villiers, a young man with dark curly hair and green eyes whom she recognizes from the party. He greets her politely but calls her "Winnie."

Grace warns Gwyneth privately to trust no one. Lucy and Paul believed the Circle of Blood, the completed collection of all 12 travelers' blood in the chronograph, should never be closed because the secret it would reveal could grant dangerous power. Grace warns that Count Saint-Germain, one of the 12 time travelers, can reportedly read minds and control wills. Despite her mother's caution, Gwyneth decides to meet the count, wanting to stop being kept in the dark. Before Grace leaves, Gwyneth overhears Gideon comforting Charlotte and expressing doubt that Gwyneth could catch up with Charlotte's years of training.

Dressed in a Rococo-era gown, Gwyneth travels via the chronograph with Gideon to September 1782. They coach across London to meet Count Saint-Germain, who is displeased that Gwyneth is not the well-prepared Charlotte. As Gwyneth prepares to leave, the count communicates with her telepathically and she feels an invisible hand grip her throat from across the room. He warns her not to break his rules, leaving her shaken.

During the return ride, three men ambush them and kill their coachman. Gideon fights with his sword, and Gwyneth, unable to watch him be overwhelmed, stabs one attacker with the dead coachman's blade. They travel back to the present before they can learn who sent the attackers. At her door, Gideon quietly acknowledges she may have saved his life.

The next morning, Charlotte coldly declares the gene is "wasted" on Gwyneth. At school, Lesley presents research revealing Count Saint-Germain as a genuine historical figure whose followers believed he possessed the secret of immortality. The friends theorize that this secret may be connected to the Circle. After school, Gwyneth sees Gideon talking tenderly with Charlotte and kissing her cheek, which sparks a pang of jealousy.

Mr. George reveals a complication: Gideon visited Gwyneth's great-great-grandmother Margaret Tilney, the Jade time traveler, to collect her blood for the chronograph, but Margaret refused. She demanded to negotiate only with Gwyneth Shepherd, a person not yet born at the time of the warning. Lucy and Paul must have traveled to the past after Gwyneth's birth to alert Margaret, though travelers cannot visit any period within their own lifetime. Gideon suspects Lucy and Paul may be luring Gwyneth into a trap.

Gwyneth and Gideon travel to June 1912 to visit Margaret at her Belgravia home. Before Gwyneth can ask questions, Paul and Lucy appear. Lucy is emotional at seeing Gwyneth. They insist the count has brainwashed Gideon, but Gideon draws a concealed pistol and forces their escape. As they flee, Lucy urges Gwyneth to ask her grandfather about a cryptic subject she calls "the Green Rider" and warns her never to visit the count again. They take refuge in the confessional of a nearby church to wait out their remaining time.

Inside the confessional, the tension between Gwyneth and Gideon shifts. Gideon admits Gwyneth makes things more complicated but also "kind of amusing." He concedes that even he or Gwyneth might someday unknowingly provide Lucy and Paul with the information they used, since time travelers can visit any point before their own birth. He touches Gwyneth's face, tells her she is "totally, absolutely extraordinary," and kisses her. They travel back to the present mid-kiss.

An epilogue returns to Hyde Park on June 24, 1912. The unnamed couple from the prologue, now identifiable as Lucy and Paul, confirm that Gwyneth is their daughter, marveling at seeing her as a teenager only two months after holding her as a newborn. Paul distrusts Gideon, while Lucy observes that Gwyneth is in love with him. Lucy senses danger approaching. Paul asks if she is ready, and she replies, "Ready when you are," echoing the prologue and signaling that their fight is far from over.