The battle against the Observers takes a heartbreaking toll, as  ‘Fringe’ season 5 returns for its fourth episode of the final season, where the team utilizes past Fringe case artifacts to stage a daring heist from a train station, and re-unite with an old friend in a mission that comes with a heavy price.

Last time’s ‘Fringe’ episode “The Recordist” saw the team finding a colony of diseased historians that may have held the key to the first stage in Walter’s plans to defeat the Observers, so how does “The Bullet That Saved the World” keep the final season in motion?  How will season 5 of ‘Fringe’ close out the epic saga?

Read on for your in-depth recap of everything you need to know about ‘Fringe’ season 5 episode 4, “The Bullet That Saved the World!”

On a largely desolated Massachusetts street, Peter siphons gas from a nearby car, before entering a local pawn shop and observing some of the relics (including a Simon!)  Just as Peter prepares to ask the clerk for what he wants, an Observer steps out with a necklace chain, having read his thoughts that he needed it.  Doing his best to remain calm, Peter tries to fill his head with random thoughts of baseball, confusing the Observer, who realizes Peter is attempting to avoid being read.  Peter briskly walks out, but the Observer alerts local loyalists, causing Peter to flee into the sewers, and is nearly killed by an exploding light grenade!

Meanwhile back at the lab, Walter and Astrid liberate the next tape, before Peter shows up superficially bloodied and bruised.  The encounter instills a sense of doubt that they can out-think the Observers generally, but Etta assures them that with time she can teach everyone to block out Observer readings.  With that, Peter gives the necklace chain to his daughter, which she had previously given up to make Walter’s laser.

Back at the pawn shop, Captain Windmark quizzically plays with the Simon, before the elder Broyles arrives.  Observing a recording, Windmark fails to understand why a fugitive Peter would risk his life for such a small gesture, also informing Broyles that a man in his division failed a security test.

Meanwhile at the lab, tape 2’s damaged state prevents the team from learning anything vital, but Walter at least recognizes that a tube full of important data seen in the footage would have been left at a very personal hiding place, a secret spot at Newark Penn Station from when he was a boy!  That said, given how many Observer/Loyalist checkpoints lie between, it won’t be easy.  Cue Walter leading the team into his personal cellar of Fringe case artifacts, any one of which might make for a fine diversion!

Over at an Observer stronghold, Broyles watches as an Observer interrogates the Loyalist who failed a security test, believing him to be a member of the Resistance.  While Broyles watches in apprehension, the Observer mentally probes the man, hearing fragments of a thought about Resistance member “The Dove.”  The Observer reports back to Broyles, who keeps his gun at the ready, as the oppressor explains that the man’s thoughts suggested the Fringe team might be hiding in the old Harvard laboratory.

Back in the lab itself, Walter, Olivia and Astrid set up their old weapons, while Etta explains to her mother how she found the bullet on her necklace in the remains of their old home, and kept it to feel closer to her parents.  Olivia explains that Peter always called it “The Bullet That Saved the World,” but they’re soon interrupted by a text from Etta’s contact (Broyles) that the lab has been compromised!  Walter points out that they’ll need the lab and all the information within, rather than permanently abandon it, ultimately resolving to re-amber the equipment for now.  Windmark figures out that Etta might be able to hide her thoughts from the Observers, meaning others could as well.

Later, Walter alone pulls up to the Observer checkpoint outside Newark Penn station, pretending to be lost before putting on a gas mask and spraying the men with the compound from season 1 episode "Ability" sealing their faces shut!  While the guards receive an alarm that the checkpoint was breached, Walter and Peter search downstairs for the spot where Walter hid his tube.  Fighting their way through the station with Olivia and Etta on perimeter, the four manage to recover the plans and escape, leaving a whole lot of dead, face-sealed Observers and Loyalists.  Windmark observes the carnage of the scene, before realizing that one of the guards put a tracking device on their car before he died.

Elsewhere, Walter unravels the tube to find a complicated mess of physics and equations that he himself can’t comprehend, but that September might be able to.  Before they attempt anything further however, Etta announces that Broyles wants to see his former friends and teammates!  Broyles pulls up, joyfully reuniting with everyone, explaining how he put Etta in his division once he recognized her to be Peter and Olivia’s daughter.

Broyles leaves a cache of weapons for the team, only to see an Observer appear out of nowhere behind Olivia!  Their position compromised, Broyles heads off to maintain his cover, while the others fight their way to a local warehouse.  In the ensuing firefight, Peter and Olivia get separated from the other two, as Etta instructs Walter to hide until they’re safe.

Alone, Etta finds herself confronted by Windmark, pressing to ask why Peter bought her the necklace.  Pushing past the woman’s mental blocks, Windmark reads Etta to see her memories and understands that the reason was love.  Etta tries to get out from Windmark’s hold, but the Observer casually shoots her in the chest, and leaves her to die!

Having heard the shot, Olivia, Peter and Walter find Etta on the verge of death, as she reveals that she’s holding one of the anti-matter bombs Broyles gave them.  Olivia tearfully tells her daughter how much she loves her, taking back the bullet necklace, and Peter nearly refuses to leave her side, as the three reluctantly depart their fallen daughter.  Tears, y’all.

Shortly after, Windmark and the others sweep the building for signs of the remaining team members, believing they’d go back for Etta.  When they find her body however, Windmark notices the bomb, which explodes in a flash of light, erasing the entire building and all inside from existence.  Windmark watches from a distance however, having teleported away at the last instant.

From a distance, Peter too watches the explosion, as Walter presses his grieving son that they need to leave.

Yeesh.  Just...yeesh.  We knew that 'Fringe's final season would move with a swift pace and pull very few punches given its 13-episode duration, but we never could have expected that "The Bullet That Saved the World" would come at the cost of Etta (Georgina Haig)'s life.  A new character though she may have been, Etta seemed the best remaining hope for the future, one that Peter and Olivia will have to bittersweetly enjoy should Walter's plan succeed, and they survive as well.  The episode also features some nice callbacks to past 'Fringe' episodes, making it one of the more action-packed and satisfying episodes of the season to date, but...yeesh.  Nine more episodes to go, and we're guessing things only get darker.

Did you get your fill of freaky ‘Fringe’ drama?  What did you think about the season’s fourth effort? Will you miss Etta?  Join us next week for another all-new ‘Fringe’ episode recap of “An Origin Story” on FOX!