On a Sunday morning, Lupo, Henry, Allison and Kevin worship at Eureka's sparsely attended church, where Reverend Harper, a former physicist, preaches. Suddenly, across town, Zoe loses her voice in an instant. She can't speak a word. Later that day, Allison's skin begins to glow. Stark diagnoses it as a form of bioluminescence and discovers that it is wreaking havoc with her nervous system. If it can't be stopped, Allison will die.
Meanwhile, the biologist Seth Osborne witnesses the water in one of his aquariums apparently turn to blood. Jack, already worried about Zoe and Allison, spots a vital clue at the scene: the aquarium's crystalline glass filter has a hole burned through it. Jack has found a similar hole in the crystalline glass skylight Zoe was sitting beneath when she lost her voice, and he soon finds a matching hole at Allison's house. All three incidents are related.
Other townsfolk have reached the same conclusion, but for a different reason. Reverend Harper is encouraging everyone to see the events through a Biblical lens as signs from God. Jack theorizes that Harper - with her scientific background - has deliberately created the crisis to increase attendance at church. If so, it's working: when the town suddenly loses electricity and plunges into darkness, people flood the church.
Harper denies involvement. At the church, however, a burst of radio interference over the loudspeakers catches Jack and Henry's attention. The church uses a crystal radio system for its music, and only specific infrasonic radio frequencies can interfere with it.
Henry concludes that such unusual and powerful radio frequencies, if broadcast around town, could melt holes in crystalline glass, agitate microorganisms in Osborne's aquarium until they caused a red tide effect, paralyze Zoe's vocal chords and even react with Allison's skin, making her glow.
Now knowing what caused the weird events, Jack and Henry can pinpoint who caused them: Diane Lancaster, the church's musical director and the head of acoustic engineering at Global Dynamics. At her home laboratory, they interrupt her in the final stages of opening a temporal rift. In fact, all the incidents around town have been mere side effects of this secret research.
Diane fervently believes that she has discovered a door to an infinite multiverse - a.k.a. heaven - where her husband, who died recently, awaits her. She wants to step through, not caring that the act will probably only kill her. Jack must stop her. Worse, he's on his own, because Henry's longing for his long-lost Kim has been reawakened by Diane's faith. Henry, too, now wants to step through the dangerous portal to see if anyone is waiting on the other side.
special guest star
TERYL ROTHERY as Diane Lancaster
We take you around the final day of shooting on the set of 'Eureka.'