The prophetic old man of the sea occurs in the earliest legends as a subject of Posiedon and is described as seeing through the whole depth of the sea, and tending the flocks (the seals) of Poseidon. At midday he rises from the sea, and sleeps in the shadow of the rocks of the coast, and around him lie the monsters of the deep. Anyone wishing to compel him to foretell the future, was obliged to catch hold of him at that time; he, indeed, had the power of assuming every possible shape, in order to escape the necessity of prophesying, but whenever he saw that his endeavours were of no avail, he resumed his usual appearance, and told the truth. Proteus has a general meaning of "versatile", "mutable", "capable of assuming many forms".
In a very intense episode The Machine gives out six names at once. All except one of the names belong to people who have gone missing over a period of years.
A serial killer has taken on the identities of his victims over time, living their lives after having observed them for some time. As a huge storm moves in Reese chases the killer to a small island outside of New York City that is soon cut off from everyone. One of the handful of people remaining on the evacuated island is a chameleon like killer, waiting to assume the identity of someone new so that they may escape undetected.
This is one of those classic setups where a small group of people are cut off from eveyone and they are picked off one by one. Reese races to figure out which of them is the Proteus like shape changing ruthless killer, incredibly joined by Harold in the thick of the storm via bi-plane.
Nice side story with Carter trying to ignore Cal Beecher's attempts to establish a personal relationship after being turned down for the FBI post because of her relationship to Cal, a dirty cop according to the FBI. They appear to have a confrontation on the topic of his activities but they don't show the entire conversation so you don't know. It is possible he is innocent. I've been wishing Carter and Reese could have a romance, but if Cal is a wronged man then maybe he is the one for her. Love Carter.