Walter goes to the alternate universe to help investigate an event that ties to both worlds.
Flee is buried as his mother spouts off the most cliched line in the history of moving pictures.
People are literally popping up dead, as if they've been involved in a plane crash, even though they weren't on a plane. Turns out a plane crashed in the alternate universe and caused a ripple effect. Walter goes to the other side to check it out.
Through some testing, Walter posits that the plane crash was caused by some device. A scene with David Robert Jones validates this theory as he acknowledges it was a test.
Jones then shows up at Froyles' home and we discover that the colonel's traitorous ways are motivated by his love for his son and a need to see him healthy. Apparently DRJ has the ability to make that happen.
Astrid gives a happily surprised Fastrid some coffee, as the two sides investigate yet another death, and the doppelgangers act as go-between. The investigation turns up a device the teams attribute to David Robert Jones.
Froyles bonds with Walter's terrible decision making related to saving his son. This seems to motivate him to continue his traitorous ways as he meets with DRJ to take possession of a device that needs planting.
A drunk Fauxlivia discusses the mole problem at her department, that led to the death of Flee, with Walter. She appears emotionally spent. Walter comforts her with food. They spitball some ideas about who the mole could be and decide it would have to be someone high up. Walter offers up the colonel. Fauxlivia shoots him down. He counters that no one should be above suspicion. This seems to have an affect on her of some kind and leads her to go talk to the recently captured Fina. She tells her they have already arrested Froyles as the mole. Fina buys the ruse and gives him up.
At Liberty Island, Froyles seems to be carrying out his nefarious mission for Jones, with Lincoln and Fauxlivia in hot pursuit, but instead has turned himself and the device in to Broyles.
As Walter returns home, Lincoln stays behind to help Fauxlivia.
Back at Walter's lab, he tells Pacey Poof and Olivia that had Froyles successfully planted his device, Jones could collapse both universes.
Walter: It's a miracle we made it in one piece! You drive like a daredevil!
Astrid: For the eleventh time, Walter, I drive the speed limit.
Walter: Most automobile fatalities occur driving between work and home.
Astrid: Yes, so does most driving.
Fauxlivia: Do you think that someone could have caused this?
Walter: On purpose? Anything is possible, even Santa Claus.
Lincoln: You couldn't bring over a casserole but a severed hand is okay?
Fauxlivia: Can't you sleep? Was the bed too hard?
Walter: No, I was sleeping like a baby. Sadly, my bladder was not.
If I had to rate this episode, and the stench from Flee's rotting corpse demands I do, I'd give it:
84 out of 100
The episode had some good scenes between characters but the Walter and Fauxlivia sequence, in her apartment, could have used more time. I still find Lincoln to be a massive bore. And the answer to the case seemed way too obvious early on, so Walter's final words didn't have the intended impact.