Invasion
Season 1, Episode 17: The Key
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Mariel begrudgingly performs an ultrasound when Christina demands to know what is growing so quickly inside of her. After the school reopens, Jesse is bothered by the way; some of the fellow students are acting. Russell and Dave investigate what Healy knew about the hybrids.
All Episodes - Season 1
Episode 1
Pilot
Episode 2
Lights Out
Episode 3
Watershed
Episode 4
Alpha Male
Episode 5
Unnatural Selection
Episode 6
The Hunt
Episode 7
Fish Story
Episode 8
The Cradle
Episode 9
The Dredge
Episode 10
Origin of Species
Episode 11
Us or Them
Episode 12
Power
Episode 13
Redemption
Episode 14
All God's Creatures
Episode 15
The Nest
Episode 16
The Fittest
Episode 17
The Key
Episode 18
Re-Evolution
Episode 19
The Son Also Rises
Episode 20
Run and Gun
Episode 21
Round Up
Episode 22
The Last Wave Goodbye