Ian returns to the Ridge in ily
In October 1774, he takes Brianna on a three-day trip to the woods, where he shows her a skeleton of a mammoth. He also tells her the story of his marriage to Wakyo'teyehsnonhsa and the death of their des himself, and Brianna comforts him. Putting great trust in Brianna, Ian then asks her whether he should stay on the Ridge or go back to the Mohawk to his ex-wife. At first Brianna feels that she can't make the ily and the responsibility does lay in her hands, and so she gives him her opinion. Ian follows her advice and stays.
In August 1775, when Brianna is taken by Neil Forbes and Stephen Bonnet, Ian interrogates Forbes and cuts his ear off. After Brianna's return to the future, Ian misses her and the fact he could say anything to her.
Brianna encounters Stephen Bonnet in a bar in September 1769 in Wilmington. She notices that he is in possession of her mother's gold wedding ring. He flirts with her, and when she asks for more information about the ring, he invites her to meet him at his ship, the Gloriana. When she arrives there, he rapes her, giving her the ring as payment for his enjoyment.
Later, when Bonnet is arrested for smuggling and is imprisoned in Cross Creek, Lord John Grey accompanies Brianna on a visit to see him. Grey waits outside as Brianna confronts the condemned Bonnet, revealing her pregnancy and telling him that he is the father. Bonnet then is aided in an escape attempt by Sergeant Murchison. The attempt is partially thwarted by Brianna when she knocks Murchison unconscious. Bonnet leaves Murchison to die as the building begins to burn, but at Brianna's insistence, he relents and carries out the similarly incapacitated Grey. Once they are safely away, Bonnet tells Brianna he has a ship waiting. He asks if she'll go with him; she declines. Before he departs, Bonnet gives Brianna a black diamond "for [the baby's] maintenance." 
When Bonnet attempts to kidnap Brianna's son Jemmy in Wilmington, Brianna shoots him in the groin, which Claire later learns resulted in the loss of one of his testicles.