"The Arrival" was the weirdest episode of Fringe yet–a deep-down sci-fi spookfest that minimized the show's procedural side and instead raised far more questions than it answered. In fact, I can't think of any questions that "The Arrival" satisfactorily answered–not even "What happened in the Fringe episode entitled 'The Arrival'?"
The cold open takes place at a diner in Williamsburg, Brooklyn, where an eccentric bald man scrawls runic language in a journal while observing a construction site through futuristic binoculars. He observes just long enough to witness a cruddy CGI explosion, which causes everyone on the street to flee (presumably while listening to TV On The Radio or something). The Observer's last pre-credits words: "It has arrived."
"It" is some kind of cylindrical machine that generates blue lens flares. (Or, as Peter calls it, a "giant metallic suppository.") Though Walter is initially reluctant to reveal what the device is, he does cop to the fact that it's sending a signal of some kind. That signal draws the attention of a stocking-capped thug (played by fine young character actor Michael Kelly, who in the right light looks a little like Steve Martin). The thug wields a zap gun and carries a pocket full of wires and electrodes that he shoves up people's noses, so that he can read their minds. In order to locate the beacon, the thug kidnaps Peter, wires him up and asks, "When was the last time your father kissed you?"
Meanwhile, Olivia is hot on the trail of The Observer, whom she spots in a photograph of a crime scene and remembers from a prior photo. Her boss Broyles is impressed that it only took Olivia three weeks to make a connection that it's taken the agency three years to uncover. Which, frankly, doesn't reflect well on the agency, since The Observer stands out about as much as this guy:
The other big Olivia event this week occurs right before the closing credits, when her supposedly dead, allegedly evil ex-partner John Scott shows up in her apartment. The how and why of John's return will surely be explored when the show returns in two weeks. Tonight, his sudden appearance just seemed part of "The Arrival"'s general goal of random mindfuckery. Also part of the plan? The big climactic scene in the graveyard, in which Mr. Stocking Cap fights with Olivia while Peter wrestles with The Observer and discovers that The Observer can recite what Peter is thinking, line-for-line. Prior to all the tussling, the beacon burrows into the earth and disappears, prompting The Observer to comment, "Departure on schedule."
The ramifications of all this will take a while to play out, though the action in this episode does seem to have an immediate purpose: to provide a reason for Peter to stick around, rather that returning to his glamorous con-man lifestyle. After talking with The Observer–or having The Observer talk for him, I should say–Peter now believes in The Pattern, and wants to stick around to see how it plays out.