“These bodies were dissected, but that’s not what killed them. High concentration of osmium in their blood; they all have toxic levels.”
– Walter

Early in its run, Fringe was very much focused on weird science. Each episode would feature some supernatural scientific phenomenon that Walter would discover through a series of wacky experiments in his lab. But somewhere in the middle of the second season, Fringe began moving away from that format and focusing more on its mythology. “Os” returns the show to that early-season-1 vibe with a case about floating bodies. However, the whimsy of that mystery belies a dark undercurrent lurking beneath.

The floating bodies at the centre of this episode’s case have high concentrations of osmium, the densest element, in their blood. Yet somehow, they’re lighter than air, which puzzles Walter. When he finds out that the osmium is bound to lutetium, yet another dense element, he’s even more flummoxed. He begins to realize that the phenomenon he’s witnessing is possible only because the laws of the universe have been flipped on their head. But this time, it’s not the fault of ZFT or some disgruntled former Massive Dynamic employee. It’s Walter’s.

When Walter crossed over to the Other Side more than fifteen years ago, he forever damaged the fabric of both universes. He has already witnessed the extent of the damage Over There, and now, he’s starting to see that same damage Over Here. Osmium and lutetium shouldn’t bind, and even if they could, they shouldn’t form a lighter-than-air substance. It’s only a matter time before the problems go beyond simple chemistry and start to affect the universe in more noticeable ways, like black holes and vortexes. Eventually, this damage will unleash a chain reaction of chaos, as demonstrated so aptly by Walter with a soda and candy eruption.

Still, the most chilling thing about this episode is that osmium and lutetium can now bind together. Walter realizes that what he did hasn’t just caused death and destruction; his trespasses have altered the laws of the universe on a fundamental level. Anybody can cause destruction with a sufficiently powerful weapon. But changing the way the laws of physics and chemistry work is something no human should be able to do.

Thus, this episode’s case acts as a wake-up call for Walter. He must figure out how to save the universes before it’s too late. Otherwise, the laws of the universe might be altered so severely that the world will come apart at its seams. And when it does, it’ll cause much more destruction than a handful of candies dropped in a cola bottle.

For more information on the Fringe rewatch project, please click here. For my review of “Os,” please click here.