After the disappointing previous seasons of Enterprise, season 4 is a major turn at warp speed in the right direction.
This season is full of some of the greatest star trek episodes ever. With a new and experienced lead writer in the show, the episodes stay true to the original trek formula and the majority of the episodes pay wonderful homages to many of the original star trek storylines and give some fascinating explanations to some of the unanswered questions in trek lore. Many of the major continuity errors made previously are cleverly corrected, whilst previous Enterprise storylines are still built upon and also allow the shows characters to have a lot more depth than before, making them a whole lot more interesting and likeable.
Highlights include run ins with the augments (a storyline involving the Eugenics Wars and the genetically enhanced superhumans, leading to The Wrath of Kahn), the Vulcan civil war, explanations for why the Klingons had a lack of facial ridges in the original series, and an absolutely outstanding mirror universe two part episode, which directly pays homage to the original series. Throughout this season we begin to see the gradual build up to the birth of the united federation of planets, and much more.
Overall, season 4 is a superb season full of action packed entertainment, which will keep you enthralled all the way through. However, the last episode is a complete disappointment to such a brilliant season, so beware. Sadly, the turnabout to the show came too late and it was cancelled at the end of production of this season. But, as a trek fan, I can honestly say that season 4 of Enterprise really does hit the spot and finally proves the show as true star trek, but it will leave you wanting more.