Blackwater (Season 2, Episode 9)

"Blackwater" is the ninth and penultimate episode of the second season of HBO's medieval fantasy television series Game of Thrones. The episode is written by George R. R. Martin, the author of the A Song of Ice and Fire novels of which the series is an adaptation, and directed by Neil Marshall, his directorial debut for the series.

The entire episode is dedicated to the climactic Battle of the Blackwater, in which the Lannister army, commanded by acting Hand of the King Tyrion Lannister, defends the city of King's Landing as King Stannis Baratheon's fleet stages an attack at Blackwater Bay. Unlike all previous episodes, "Blackwater" does not follow the parallel storylines of the characters outside of King's Landing.

https://en.wikipedia.org/wiki/Blackwater_(Game_of_Thrones)