Threshold

Season 1

Trees Made of Glass (1)

Episode 1

Trees Made of Glass (1)
Trees Made of Glass (2)

Episode 2

Trees Made of Glass (2)
Blood of the Children

Episode 3

Blood of the Children
The Burning

Episode 4

The Burning
Shock

Episode 5

Shock
Pulse

Episode 6

Pulse
The Order

Episode 7

The Order
Revelations

Episode 8

Revelations
Progeny

Episode 9

Progeny
The Crossing

Episode 10

The Crossing
Outbreak (a.k.a. Escalation)

Episode 11

Outbreak (a.k.a. Escalation)
Vigilante

Episode 12

Vigilante
Alienville

Episode 13

Alienville