One issue resonates through this thrilling, horrifying episode: there are many ways to be imprisoned, and taking prisoners does not necessarily mean you are entirely free yourself.

In a busy, rushed episode, characters find that holding on to power is trickier than taking power, and that refusing to show mercy can be as dangerous as showing mercy.

The mysticism mounts and the death toll rises, in an episode that tells us power is not necessarily about having overwhelming force: sometimes it’s about having a little bit, and leveraging it.

The first three episodes have concerned what power is, how it works and how it’s attained. Episode 4, “Garden of Bones,” is about what power does. It creates monsters.

The first season demonstrated, to the chagrin of Headless Ned, that it is not necessarily honorable men who win out. The second season, at least as “The Night Lands” suggests, is showing that it sometimes takes a dishonorable man to get the job done.

While Game of Thrones is steadily expanding — just look at the new pit stop on the map flyover in the credits — “The North Remembers” began hustling off steadily and confidently.