His Dark Materials 2x4 -

: Lyra and Will must use the knife to retrieve the Alethiometer from Lord Boreal (Sirs Charles Latrom), who stole it from Lyra earlier in the season.

: Will fights for and wins the legendary Subtle Knife (Æsahættr) from Giacomo Paradisi, the current bearer, in a brutal struggle that costs Will two fingers—the mark of the knife's bearer. His Dark Materials 2x4

For those looking for a deeper dive, the episode breakdown on Reddit is highly recommended as it recaps the major emotional beats and technical lore of the Subtle Knife. : Lyra and Will must use the knife