A Storm of Swords
"The Climb" is the sixth episode of the season written by showrunners David Benioff and D. B. Weiss, and 18th overall. It is based upon George R. R. Martin's novel "A Storm of Swords", namely, chapters 30, 35, 37, and 48 (Jon IV, Catelyn IV, Jaime V, and Samwell III).