Crossbones season 1 episode 6
Episode title: A Hole in the Head
Balfour overhears Lowe confess to Kate of being an English spy sent to kill Blackbeard and he tells Selima, who sends pirates to find Lowe. Antoinette's torture continues at the hands of Jagger, now using Lowe's sketchbook as evidence that Edward "Blackbeard" Teach is alive.
