In brief: Further issues of human/Vulcan trust prove reasonable, and I thought the chase plot was pretty well executed.
There's nothing particularly groundbreaking about the storyline in "Fallen Hero," but it does a good job of using its characters, creating some conflict, and ultimately finding its way in an extended, well-directed chase plot.
The dialog and character interaction is good enough and nicely acted, but it's not the real selling point of this episode, in my opinion. Where "Fallen Hero" proves best is on the level of its understated action and its chase, where the Enterprise is tested on the basis of its engines and its crew's tactical ingenuity.
The mission: Escort a Vulcan ambassador from the planet Mazar and deliver her to a Vulcan ship with which the Enterprise will rendezvous. The catch: It turns out the ambassador, V'Lar (Fionnula Flanagan), has been expelled from the planet for committing an unspecified act of misconduct, something about which she's not at all forthcoming in disclosing. The Vulcans weren't even willing to explain why they needed V'Lar picked up when they asked the Enterprise go on this mission in the first place.
Archer certainly isn't happy about being left in the dark by the Vulcans yet again, but things get more complicated when a Mazarite ship comes after the Enterprise and requests — no, demands — they turn the ambassador back over to them to answer for unfinished business. When the Mazarite ship opens fire, Archer flees the scene, but V'Lar still won't reveal why she was forced from Mazar. Archer subsequently turns the ship around with the intention of handing V'Lar back over to the Mazarites. After all, why should he risk his crew's lives for a mission whose details he's not even granted access to?
One nice moment is Archer's discussion with Admiral Forrest (Vaughn Armstrong), who understands Archer's situation and his decision to abandon the assignment. Forrest's acknowledgment, "I'm not out there; you are. It's your call," seems quite reasonable given the reality of Enterprise's situation — alone, and solely facing the immediate consequences of what goes on out here.
If there's an aspect of the episode I didn't quite find convincing, it's V'Lar's refusal — given Archer's new decision to turn her over — to share the truth with him, especially given that it's not particularly sensitive information from where the Enterprise stands. It doesn't seem logical so much as simply distrusting — perhaps too much so — of humans.
What we have here is a continuation of one of this season's themes, which is the issue of the strained relationship and mutual distrust between humans and Vulcans — a situation that slowly is getting better. The theme is revisited in a mostly believable matter that proves consistently watchable, if not entirely absorbing. Also here is a personal complication for T'Pol, who regards V'Lar as one of her heroes of youth (although she wouldn't admit it in so many words). The topic of V'Lar having possibly committed a crime on Mazar is something that is unsettling for T'Pol.
V'Lar explains that the Mazarites have corrupt politicians in their midst that are responsible for her current predicament, and after a personal request from T'Pol — an action worth noting — Archer reluctantly agrees to protect V'Lar so she can eventually testify against the corrupters on behalf of the legitimate Mazarite people. This is all fine and good, though the issues of Vulcan/human trust are not explored in especially deep or subtle ways.
What's more exciting is the story's execution over the Enterprise being chased by the corrupt Mazarites, who have a ship that isn't much faster than the Enterprise, but is just fast enough to maintain a slow and steady gain. The pressure of the situation builds slowly and quietly, until we realize that a fairly standard action concept has been supplied enough momentum to be genuinely entertaining. We've seen the Pushing the Engines to the Limits [TM] routine before, but it comes across effectively here because of how untested the Enterprise is. (Archer: "They call it a warp 5 engine." Trip: "On paper.")
The final act — as the tempo increases and the game goes down to the wire — features some top-notch directing/editing/cinematography. Patrick Norris, a director I haven't seen in Trek before, keeps the camera on the bridge moving around with a semi-chaotic fluidity (an oxymoron, I know, but that's the best description that comes to mind). It has the effect of upping the pace without calling too much attention to itself — very well done.
Also enjoyable are the various exchanges between Archer and the Mazarite captain (John Rubinstein), including the way Bakula answers terms of surrender with, "I have a better idea: Why don't you slow down before your engines explode." Archer's stalling efforts once the Enterprise is trapped also prove fun, probably because they are simultaneously desperate, amusing, and convincing. (The Mazarite captain isn't always fooled, which is also appreciated.)
As Vulcans go, V'Lar is a pleasant departure, showing that Vulcans need not always be portrayed in the same emotionless monotone and with unilateral disinterest in human traits. Indeed, V'Lar is the most individual-seeming Vulcan in some time, and still comes across as a Vulcan. The qualm I've sometimes had with T'Pol is that she doesn't come across as an individual so much as an iteration on an archetype: the perpetually cool and calm character speaking in monotone. It might be a good idea to somewhat head away from that since we've seen enough of it over the years. Heck, Voyager had two of them.
Next: Archer and Trip take a desert vacation they weren't intending.