“And Those We’ve Left Behind” is episode six of season four of Fringe.
Olivia is lying in a park when Peter comes over. They agree it’s the perfect day, but Olivia says it has to end. They can’t ignore the problem. Peter. Peter is the problem. Peter wakes in the federal building, then Olivia comes in. There’s something going on, and it might be related to Peter’s appearance. They think it has to do with time.
In Central Village, Boston, a woman is talking to her daughter in the kitchen, when suddenly the place shows signs of having been in a fire. She finds her daughter, now a baby, and rushes outside. The building has fire damage in a pattern. And her daughter becomes her normal age again.
Olivia and Peter are in the car. Olivia explains that shortly before he arrived, they had their own temporal anomalies. Strange reversals in cause and effect. Peter asks if that’s why they’re heading to Massive Dynamics and if they think this is down to him. They do. He wants to know what Walter’s theory is. Walter doesn’t have one, as he doesn’t want anything to do with Peter. Then Lincoln calls.
Astrid and Lincoln are in the apartment at Central Village. Astrid is using a device and Walter says that what happened isn’t caused by bleed through from the other universe. Broyles says there was a fire, but no cause and the damage was instant. For the duration, the girl went from 5 years old to an infant.
Lincoln reports that the fire marshals have never seen anything like it. The fire seemed to happen in a circle. And there was an other fire here four years ago. Broyles wants some tests done on Peter by Walter. Whether Walter wants to do them or not.
Walter runs the tests in the lab, calling Peter ‘the subject’ or ‘it’ whilst doing them, and then says that the subject has nothing to do with the phenomenon. Peter thinks Walter can’t be sure, but Walter is finished. Peter finds out Walter lives in the lab and asks when that happened. Since Olivia checked him out. Peter decides to work on the problem himself. If he did damage the space-time continuum, there might not be rules and the anomalies will increase and keep getting worse.
A car full of teenagers has to suddenly brake to avoid part of a train that appears on a crossing.
Peter is not getting anywhere with the equations and Olivia is categorising the events. The apartment fire is different to the others. Walter comes into the lab. He’s willing to help. As soon as his lab is available again. Olivia explains that Walter was having visions of Peter before he showed, and she was dreaming of him.
Lincoln tells them about the freight train and Peter is talking when they’re suddenly all at the scene. This event was also spherical and Peter experienced a time jump. Then he’s in the car and Lincoln reports the last train on that track was four years ago. Peter is saying this is good as it’s a pattern when he’s back at the crossing, prior to the previous time. The teenagers car is damaged and Peter detects radiation. The car’s bumper crumbles. Peter starts explaining, then he’s back in the car with the other two again. There’s neutron radiation present, and that means somebody has to be causing it.
A woman is working on an equation. Her husband is watching a timer on his watch. Just before it reaches zero, he kisses her. She’s suddenly elsewhere, suffering from what may be some kind of dementia.
Walter is listening to music in the lab whilst Peter and Olivia are working. They have two points, then Lincoln says they have two more. Walter is ready to present a theory. The points are on a golden spiral. The source will be at the centre.
It seems that the man is continually going back to four years ago, before his wife became ill. But that’s having consequences for everyone else. Peter starts wondering if he’s in the wrong place.