S4 E1: Snakes in the Garden

S4 E2: The Sting of Survival

S4 E3: Life Source

S4 E4: North Star

S4 E5: The Engineer

S4 E6: Bell the Cat

S4 E7: A Moth to a Flame

S4 E8: By Weeping Cross

S4 E9: Dominant Traits

S4 E10: Last Stop