History Series / Siren2018

* MissingMom

* KillAllHumans: Tia wants to wipe out humanity, viewing us as a deadly threat for not only her species, but the environment generally. She tries to provoke a world war that would do this.

* DisappearedDad:
Xander's dad Sean is stabbed to death by a merman who attacks them. He struggles with his loss for a long time afterward.
[[spoiler:Maddie loses her stepfather Dale, who's become her father in all but DNA, who gets killed by Tia's attack in the series finale.]]

** Maddie's mother left her and her father about nine months before the series began. It's shown the departure was not a cordial one, and resulted from her drug abuse. She later returns to mend things with Maddie, though it's difficult. Her birth father is [[AmbiguouslyAbsentParent not mentioned at all]], on the other hand.

DeathByChildbirth: [[spoiler:Ryn's surrogate Meredith dies from a heart attack after giving birth to her daughter, since the strain was too much.]]

* AmbiguouslyAbsentParent: Maddie, Ryn and Cami's fathers are unmentioned in the series, but are clearly not around or a part of their lives.

** Maddie's mother left her and her father about nine months before the series began. It's shown the departure was not a cordial one, and resulted from her drug abuse. She later returns to mend things with Maddie, though it's difficult.
** In Episode 6, Ryn reveals to Maddie and Ben that her and Donna's mother died when they were young.

* HealingFactor: Merpeople can heal much quicker, from worse injuries, than humans. Within a few days they can go from close to death and come back.

* LineOfSightName: Ryn takes her name from a cartoon seahorse. [[spoiler: This also applies to her human surname Fisher that Ben picked out for her in season 2]]

* MagicMusic: The Siren Song is apparently a defense mechanism: it's sung to distract or enthrall humans. It leads to lingering effects that Ben equates to an addiction; both he and Decker continue to crave the song long after they hear it for the first time. [[spoiler: In Season 2 Decker's autopsy reveals that the Song actually caused him some brain damage, and everyone is now worried about Ben. The BigBad of season 3 takes this one step further by weaponizing the song and launch a mass-scale attack against humanity.]]

* MinorityPoliceOfficer: Dale Bishop is the Sheriff of Bristol Cove, and a member of the indigenous Haida people in the area.
* MissingMom:
** Maddie's mother left her and her father about nine months before the series began. It's shown the departure was not a cordial one, and resulted from her drug abuse. She later returns to mend things with Maddie, though it's difficult.
** In Episode 6, Ryn reveals to Maddie and Ben that her and Donna's mother died when they were young.

* TrackingDevice: Maddie gives Ryn a pendant with one inside so they can know her location during "On the Road".

* ThreewaySex: Ben, Maddie and Ryn have sex together in 'Leverage' before going on the sabotage mission later.

* LoveConfession: Maddie tells Ryn how she and Ben love her in 'Leverage' before [[ThreewaySex the three have sex together]].

* HealingPotion: Mermaid stem cells turn out to have incredible healing effects on humans, including curing paralysis. Ben's mom, who's paralyzed initially, uses them to slowly recover.

* FieryCoverup: After Donna and Chris escaped, the military torched their facility where both had been imprisoned held to cover it up.

* OurMermaidsAreDifferent: Mermaids here are an aquatic humanoid race who are capable of transitioning into a form with legs when they have to come on land, but the transition (from land to sea, at least) is neither quick nor clean. Those who do step out of water have to eventually return to the ocean (and subject themselves to a PainfulTransformation), or their bodies literally break down and they can't change back. They have much denser bones and far greater strength than humans as a result of living in the ocean's crushing depths. Their eyes are larger than human eyes, but their pupils are smaller to compensate for the different way light behaves when traveling through water (as opposed to air). Also, only ocean water triggers the transformation, meaning Ryn can be in a bath or pool and still be in human form. Some mermaid tribes are also born [[OneGenderRace all female]], but can [[SexShifter change to male later]] for reproduction. They are apex predators organized in matriarchal tribes; their eye color marking which tribe they belong to. They have their own language and culture, but can quickly learn to adopt human ways. Their song, if used defensively, can cause severe brain damage and even drive people to commit suicide. Otherwise, it can enrapture them.

* {{Polyamory}}: Maddie is involved with Ben when the series starts. However, both soon grow attracted to mermaid Ryn, and she reciprocates. Both of them kiss her before having a [[ThreewaySex threesome]] in Season 2, where they settle on [[{{Polyamory}} all being together]] since both like Ben as well. Maddie and Ben don't tell their friends or relatives, who find out on their own, expressing surprise though accepting this.

* {{Polyamory}}: Maddie is involved with Ben when the series starts. However, both soon grow attracted to mermaid Ryn, and she reciprocates. Both of them kiss her before having a [[ThreewaySex threesome]] in Season 2, where they settle on [[{{Polyamory}} all being together]] since both like Ben as well.

* LoveTriangle: A very weird one between Ben, Maddie, and Ryn. Ryn being an siren, she has Ben under her spell (however unintentionally), and his mixed-up feelings toward her complicate his relationship with Maddie.