• The episode’s title, “Erigah”, refers a form of Breen “blood bounty” first mentioned a couple episodes ago in “Mirrors”.

• The opening shot is of the USS Locherer, first seen in “Jinaal”, and the Terran warp pod that Moll and L’ak escaped with in “Mirrors”.

• It’s Nhan! From Star Trek! Nhan was introduced in “Brother” and is played by Rachael Ancheril.

• ”Last time I saw you, also a personal situation, you fired on Discovery with photon torpedoes, and set off an isolytic weapon.” Nhan is referring to the season four episode, “Rubicon”.

• ”You did this to him!” Moll stabbed himself while in a fight with Burnham in “Mirrors”.

• ”Fierce as a sa-te kru.” This is the first mention of a sa-te kru on screen, but the cat like predator from Vulcan/Ni’Var originated in a six page comic called “When Worlds Collide: Spock Confronts the Ultimate Challenge” written by Alex Kurtzman and Robert Orci, and drawn by Paul Pope that was published in a 2009 issue of “Wired”.

• Throughout the course of the episode, outside of Federation HQ, in addition to the USS Discovery A we see:

    • Two Mars-class starships

    • USS Excalibur - 32nd century Constitution-class

    • USS Credence - Introduced in “Choose to Live”

    • USS LaMar - A ship of the same class as the USS Dresslehaus

    • USS Lochlerer - Merian-class

• The fourth piece of the Progenitor technology researchers’ map piece is now included in the opening credits sequence.

• ”Let’s not forget what happened last time Breen entered Federation space.” The last time we know for certain that the Breen entered Federation space was in “The Changing Face of Evil” when they attacked Starfleet HQ on Earth during the Dominion War, some 834 years ago. It is entirely possible that Rayner is referring to a more recent event that we the audience are unaware of.

    • Later, Tilly claims, ”The last time the Breen paid a visit to the Federation, they destroyed an entire city.” That might be a reference to the attack on San Francisco in “The Changing Face of Evil”, though it would be an exaggeration of the scale of the destruction. And again, 834 years have since passed.

• Rayner evokes the Romulan saying, ”Never turn your back on a Breen.” While in a Dominion prison station in “By Inferno’s Light” a Romulan fellow prisoner told Doctor Bashir that was a saying among her people.

• The Betazoid emblem on the clue that we will learn is a library card, was originally designed by a Trek fan named David Bilic for the “Birth of the Federation 2” mod. It was first seen on screen in “The Star Gazer”.

• The USS Mitchell was first seen in “Rubicon”.

• ”What’s worse than death?”
”This conversation, for starters.”
In “Magic to make the Sanest Man Go Mad”, Harry Mudd claimed that the weaponized dark matter beads that Captain Lorca had were rumoured to be the most painful way to die; now they need to be downgraded to number two.

• Jett Reno apparently makes a cocktail called the Seven of Limes, presumably named for the notable captain of the USS Enterprise G.

• Unlike the 24th century Breen Interceptors, the Breen Dreadnought appears to be more or less symmetrical.

    • It is stated that this Dreadnought is the one Burnham and Rayner saw outside the destroyed Federation HQ in a possible future in “Face the Strange”, though I will be honest, it was too dark for me to make out on the screen at the time.

• Burnham learned that Kellerun was used as a Breen outpost. Apparently that didn’t come up when she did the research in to Kellerun culture she mentioned in “Mirrors”.

    • Does this indicate that Kellerun is not part of the Federation, or is the attack on Kellerun the previous entry into Federation space that Rayner mentioned earlier in the episode?

• Reno claims she had ”tons of contacts in the book trade” 800 years earlier. Discovery and its crew jumped to the 32nd century 933 years earlier. I think it’s safe to assume that Reno was rounding off, however, 133 years is still a pretty big gap. This can only mean that at some point before the jump to the 32nd century, Reno also found herself in the 24th century smuggling books. I eagerly await that spin-off.

• President T’Rina bluffs Primarch Ruhn by claiming the Federation has received an offer from another Breen Primarch for Moll and L’ak. As we all know, Vulcans cannot lie.

    • Vulcans lie all the time.

• ”This bluff wouldn’t fool a hatchling.” Ruhn’s remarks imply that Breen are oviparous.

• Rayner states that Primarch Tahal named her ship the Tau Ceti ”After a lethal viper with a slow acting venom.” It’s unclear if this viper is native to the Tau Ceti system, which can be seen on star charts going back to “Conspiracy”.

• Book is able to get a psychometric reading off the library card to to figure out where the Archive is. This is the second time Book’s extrasensory abilities have been the key to solving one of the clues, the first being in “Jinaal”.

    • The reading from the library card indicates the archive is in the Badlands, a volatile region of space, conceived of for the premiere of VOY, “The Caretaker”, and first seen in the DS9 episode, “The Maquis, Part 1”.

• ”Sell me a goat farm on Bopak III while you’re at it.” Bopak III is the world where the Jem’Hadar first, Goran’Ager enlisted Doctor Bashir to try and use the locally available materials to cure his men of addiction to ketracel white in “Hippocratic Oath”.

• After stabbing himself and intentionally overdosing on medication meant to save him, L’ak dies as he lived. Stupidly.

    • In an interview with TrekMovie, series editor Carlos Cisco said that while Breen are less vulnerable in their solid form – still susceptible to self inflicted stab wounds though – the act of maintaining it requires so much energy they are slower, more sluggish, and less intelligent while doing so. This is the form that L’ak chooses to remain in.

• Rayner advocates for firing on the Breen before they can make the first move. in “The Vulcan Hello” Burnham so strongly believed that the USS Shenzhou should fire the first shot against the Klingons that she was willing to foment a mutiny to do so, a fact that she later points out to him.