S4 is stronger than S3 in that it seems to scale back on "Game of Thrones" style drama related to the former space inhabitants (who are known as Skaikru for his purpose) and the 12 tribes of "Grounders," who are humans who did not allow a little thing like an apocalypse make them abandon earth when the ancestors of Skaikru scampered off almost a century ago. The shifting alliances, betrayals of those agreements, ambushes, assassinations, and titular "civilized" teens going native is hard to follow at times.
This aspect of "100" epicly takes center stage in a "Hunger Games" style battle royale in which first prize is life and second prize is angonizing death. Grounder wannabe/lover of bad boys Octavia represents Skaikru.
S4 opens in the wake of many members of the core group returning to reality after abruptly being yanked from an idyllic state of consciousness. One of the most harsh truths that these folks and their peers face is that the impending fallout from already failed nuclear reactors makes fatal radiation exposure imminent.
The urgency of either finding a means of becoming impervious to the radiation or finding shelter that is both sturdy enough to shield people from that harmful substance and large enough to house everyone who requires that protection drives most of the S4 action. This further creates a regularly requiring need to decide more who must die so that others may have a chance of living, rather than making a tough choice related to avoiding any death at all.
On a fundamental level, having our re-pioneers face certain death from radiation poisoning gets to the core (pun intended) concept of "100." That threat is what drives humans to live in space in the first place. An early (and repeating) story arc regrading determining which 100 people to save further ties into the primary theme of this series.
Once more, teen group leader Clarke is at the center of the struggle to survive (without even any thoughts of thriving) as she attempts to keep her people sedate and to stop the grounders from attacking. One (not so abstract) aspect of this is a sense of "who died and made you queen." Facing selecting a lab rat for a possibly fatal experiment, having word of the aforementioned list leak, and having to adopt a literal bunker mentality are only a few of the challenges that are just another day at the office for this Katniss of the 100verse.
For his part, former government head Thelonious Jaha (Isiah Washington) goes from an S3 obsession with a virtual Utopia to indirectly seeking salvation via a doomsday cult. He, like his peers, further finds himself experiencing distressing deja vu.
Formerly adorkable Jasper continues his emo journey by becoming the leader of a group that chooses to party hearty for a few days and leave a not-so-pretty corpse than to merely survive. He further once more goes full Monty; this time in a hilarious shower scene that also features his repeatedly on-again-off-again pal who shares the name of this slang expression.
The multiple build-ups to the season finale further outshine the S3 (and S2) season-ending events. Knowing that not everyone can be saved brings out the best in some and the not-so-best in others; it further shows that the good deeds of a few do not go unpunished for the masses.
Meanwhile, a small group of far-out space nuts get ready to leave the world that they used to know without any plan of how to return; Raven is there to help them along.
The final scenes take a significant leap ahead in time in a manner that should have new and old fans alike counting down to the early 2018 S5 premiere. Both seeing how things in this new present (which allows the cast to literally act its age) play out and see the events that lead up to them.
The plethora of extras include a feature on the aforementioned Jasper that shows that actor Devon Bostick is just as goofily charming as his character. We further get the standard and always entertaining Comic-Con Panel for the season, equally enjoyable Gag Reel and Unaired Scenes, and a plethora of making-of documentaries.
Anyone with questions or comments regarding "100" is strongly encouraged to email me; you also can connect on Twitter via @tvdvdguy.