Charlie helps Walter examine the body. Walter sees that he looks pale and suggests that he smoke cannabis before bed to help him sleep. Walter finds a device that the shapeshifter used on the man.

Meanwhile, the robber checks a frozen head and throws it in a pit. Charlie meets with the robber and tell him that the FBI understands what the inside man is. The robber tells Charlie that he looks like he is dying and recommends that he return home. The robber checks the last head and sees that it is not the one they are looking for. Charlie says that he thinks that Olivia knows where the missing head is. The robber suggests that he make her remember.

Broyles and Olivia wonder why the shapeshifting soldiers are looking for a head. Broyles says that the other device they found is broken and is now being analyzed by Massive Dynamics. Olivia wonders if Peter can look at it. Broyles warns that the last time they came across a similar device, someone tried to kill her. Olivia figures that since the incident happened six weeks ago, she should be safe.

Walter examines the body of the inside man. He tells Astrid that the man is not human. He figures that he is composed of mercury and uses the device to take on different shapes.

Peter tells Olivia that this case reminds him of Invasion of the Body Snatchers. He hooks the device to a electronic meter and sees that it is sending out data.

Olivia gets a call from Astrid and returns to the lab. Walter reports that the blood of the first shapeshifter is different from this one. Olivia figures that the first shapeshifter is still alive and can be disguised as anyone. Walter says that he thinks he knows how to find him. He replays the tape of Rebecca, the drug induced psychic who identified the shapeshifter.

Olivia calls Charlie and tells him that she might have found a way to locate the shapeshifter. Charlie hangs up and purchases several mercury thermometers. He goes into his car, breaks them, pours the mercury in a plastic cup and drinks it. He looks in the mirror to make sure that his face is still in shape.