An Echo In The Bone flips between centuries with the horrible magic of time travel.
In the 20th century at Lallybroch, Brianna, Roger, Jem, and Mandy are reading letters from Claire and Jamie from the past, one of which mentions hidden gold, with a location known only to Jemmy. William Buccleigh Mackenzie, Roger’s Scottish ancestor, has his own accidental incident with the stones at Craigh Na Dun and appears in their time. Knowing the date of death on the family record, Brianna and Roger know he is unlikely to make it safely back to his time. Rob Cameron, one of Brianna’s coworkers, kidnaps Jem, and it appears that he has taken Jem into the past, causing Roger and William travel through time to find them; but Rob appears at Brianna’s home and orders her to tell Jem to disclose the location of the gold. Jem is locked underground at the dam where Brianna and Rob work, finds an electric train, and starts an escape; his fate is unseen.
Back in the 18th century, Lord Ellesmere, better known as Willie (actually Jamie’s son but raised as Lord John Grey’s stepson) is involved in the American Revolution as a Redcoat, but finds himself in awkward situations until the battle of Saratoga, wherein he distinguishes himself. Arch and Murdina Bug try to retrieve the gold hidden on Fraser’s Ridge, during a confused confrontation Mrs. Bug shoots Jamie when he tells her to stop, and Ian shoots her. Ian feels guilty for killing Mrs. Bug; Arch vows to take his revenge when Ian has ‘someone worth losing’. Claire, Jamie, and Ian leave their mountain home for Scotland to see Jenny, Ian, and their children, and also to recover Jamie’s printing press. On their way to Scotland their ship is attacked and ensuing events find them embroiled in the Revolutionary War.
During the course of an battlefield engagement at Saratoga Jamie shoots at the enemy. To his horror he finds he has shot the hat off William’s head. A kinsman of Jamie’s on the British side, Simon Fraser of Balnain, is killed. As part of the Terms of Surrender Jamie and Claire are asked to take his body back to Scotland. Before they leave, a stranger tries to blackmail Jamie, but Ian kills him. Claire, Jamie, and Ian leave for Scotland to bury Jamie’s relative and Ian leaves his dog Rollo with a Quaker woman named Rachel Hunter. Jamie, Claire, and Ian reach Scotland, where Ian the elder, husband to Jamie’s sister Jenny, and Jamie’s best childhood friend, is dying of consumption when they arrive. Ian and Jenny are ecstatic that young Ian has returned; but Jenny is hostile to Claire who is unable to cure Ian. Jamie apologizes to Laoghaire (his second wife) for their separation. Laoghaire’s daughter (and Jamie’s adopted daughter) Joan requires Laoghaire to marry her lover, a crippled servant, so that she (Joan) can become a nun. A letter from Laoghaire’s daughter Marsali reveals that her son, Henri-Christian, is very ill. In this missive, Marsali beseeches Claire’s help in treating him. Claire agrees to return to America to treat Henri-Christian, stipulating that Laoghaire marry her lover, stop taking alimony from Jamie, and help Joan become a nun.
Claire saves Henri-Christian’s life, with the help of Lord John, and saves Lord John’s injured nephew Henry. Lord John’s niece Dottie has come to America as well, in love with Rachel’s brother, a Quaker physician named Denzell Hunter. Claire receives a letter from Jamie that Ian has died and Jenny has decided to leave Lallybroch. Word later arrives that Jamie has been lost at sea; and Claire is about to be arrested for being a spy, when Lord John insists on marrying Claire for her protection, as well as for the protection of Fergus, Marsali, and their children. Arch tries to kill Rachel, but Ian fights him, until William kills Arch. Jamie returns alive, with Redcoats after him, and pretends to take Lord John hostage and flees; but William realizes that Jamie is his father, flies into a rage, and storms out.