A teenager walks into an abandoned warehouse after hearing an explosion. He is killed by a shape-shifter and his form is then stolen. It then goes on to kill the victim’s girlfriend and now there are two shape-shifters on the move.
Walter tries to tell his son where he is from but is interrupted by Olivia.
Newton and his shape-shifters have returned. The team notices three puncture wounds on the soft pallets of both victims. They also find the dead embryo of a shifter that didn’t survive.
The young couple, aka the shifters, meets up with Newton and begins to execute their plan. What are they up to?
When the shape-shifter embryos crossed into our universe it caused some sort of cable interference. The team is able to decipher a hidden message inside the interference. This radio interference was given off by a solar wave, in a parallel universe. Thus the timing of the radio waves would be slightly off, only lining up on rare occasion, tomorrow at 3:31 pm. This time is of great importance.
Water then comes up with a plan to figure out what Newton is up to. He rambles on about needing certain supplies, including a fresh human corpse. Walter is able to jump start the shape-shifter embryo, bringing it to life. It says Daniel Verona. Then it says “I'm sorry” and dies.
The team goes to Daniel Verona, which turns out to be a dead lead. But, Newton has already planted a rod at the city morgue.
Newton and the shape-shifters continue working on planting three metal rods at strategic places in the city. The three places are the three points to a triangle.
The two universes vibrate at different frequencies. Newton was able to set up the rod triangles in both universes and now attempts to activate them. If they vibrate at just the right frequency, whatever is in the center of both will simply be exchanged.
The team somehow guesses the exchange must be on the Charles River, on the condemned railway bridge, because the water would absorb the excess energy.
Walter formulates a plan to cancel out the vibrations. Olivia is able to kill both shape-shifters, while Water drives their car onto the bridge. Peter runs to help his father. But something goes wrong with the computer wave program. Peter stays behind to fix the program and is thrown from the blast of the vibrations. A man from the Other Side is able to cross into our universe without the team seeing.
After Peter wakes up in the hospital, he asks to speak to his father alone. He figures out that he is not from our universe because he was able to survive the vibrations, like the man from the other side.
Olivia goes to tell Walter that Peter checked himself out of the hospital and now is no where to be found.
Newton is last seen helping an unknown man recuperate. Newton tells him to relax and that he should start to feel better soon. Who is this man and why did he want to come to our universe?