The show follows four international scientists who begin to witness strange marine phenomenons that arise in tandem. They realize that these events are the result of an unknown intelligence defending the ocean, which has been historically exploited by humans.
Not to be confused with the series Swarm or the movie The Swarm (1978).
The Swarm contains examples of:
- The Big Bad: Initially an anonymous intelligence with an unknown agenda who seem to be attacking humanity randomly with mutated or mind-controlled marine life. Later revealed to be the Yrr, an intelligent microscopic species seeking to push humanity from the coast.
- British Brevity: The miniseries consists of only eight episodes.
- Devious Dolphins: The first episode ends with a pod of orca attacking a whale watching boat and killing many of the tourists aboard.
- Face Death with Dignity: In the fifth episode, Tina realizes that she has no chance of getting to high ground before the tsunami hits her, and thus she chooses to wait in her car, leaving a final message to Sigur.
- Flat-Earth Atheist: Prof. Lehmann utterly refuses to believe that there could be something intelligent behind all the phenomena that have been affecting the ocean, despite all the evidence.
- Global Warming: The climate catastrophe is wrought by the Yrr, but the Arctic and Antarctic ice melting is the reason they are seeking retribution.
- Hive Mind: The researchers learn that the titular "swarm", or the Yrr, functions in this way, to the point where they can even merge with and control other marine animals.
- Incurable Cough of Death: The Vibrio vulnificus causes a nasty persistent cough that eventually causes people to cough up blood and die.
- Insufferable Genius: Charlie Wagner's career has stalled because while she is extremely bright, she lacks any patience or tact and constantly butts heads with her superiors. According to Prof. Lehmann, this runs in the family; Charlie's mother, Ingrid Haugen, was almost exactly the same way.
- Mass "Oh, Crap!": In the fifth episode, reports of a sudden tsunami about to hit Norway and the Shetland Islands sends most of the cast scrambling to get Charlie and Sigur to safety.
- Monster Whale: This series offers excellent reminders of why people used to fear whales, as the normally amiable humpback whales suddenly turn hostile and start attacking ships. In the first episode, whales attack a whale-tour ship, sinking it and nearly killing everyone aboard.
- Obstructive Bureaucrat: As the protagonists all gather together to exchange theories about the various phenomena they've witnessed in their respective fields, their attempts to form a thesis and present it to the wider scientific community are stymied by Prof. Lehmann, who is more concerned about her subordinates possibly damaging the reputation of her institution.
- Properly Paranoid: After realizing that the water in Venice is contaminated and that they have no idea how far the contamination has spread, Cecile packs her kids off to somewhere inland to keep them as far away from the water as possible.
- Reassigned to Antarctica: Charlie was banished to a remote outpost in Scotland after doing something to piss off Prof. Lehmann.
- Sacrificial Lamb:
- The second episode sees Jess, Charlie's best friend, die when the Juno sinks.
- The fifth episode sees Tina Lund and Douglas MacKinnon get taken by the tsunami.
- Screw the Rules, I'm Doing What's Right!: Jack Greywolf O'Bannon was discharged from the US Navy for freeing the dolphins that he'd trained for service in the Middle East rather than let them be put down.
- Screw This, I'm Outta Here: After realizing that Hovedstad exploited her and her relationship with Sigur to get permits, Tina Lund resigns from her job,
- Spotting the Thread: In the third episode, Leon Anawak discovers that the pattern of the whale attacks matches the local whale migration patterns.
- Twofer Token Minority:
- Dr. Rahim Amir is an Arab man in a relationship with another man.
- Dr. Samantha Crowe is a married black lesbian.
- When You Coming Home, Dad?: On top of everything else she has to deal with, Cecile has to deal with an ex-husband who keeps leaving their kids at home without babysitters while he goes away on business trips.
- Working with the Ex: Dr. Sigur Johanson used to date Hovedstad executive Tina Lund. It makes things very awkward between them when Hovedstad hires Sigur to do a survey for them.
