Three new writers were added to the B7 pool for the second season, with the first script not by creator Terry Nation or story editor Chris Boucher coming from Allan Prior. Co-creator of Z-Cars, Prior would write five times for the series, with three of them in season 2. None of them are all that good; indeed, if you were to quickly scribble a list of the ten worst episodes there's a decent chance he would have half of it sewn up. "Horizon" is probably his best and it ain't great, though it is difficult to put a finger on exactly why.
The title comes from the codename of a Federation occupied planet. At this stage the occupation is superficially benign, a mission to elevate the primitive people that seems to have been initiated by ruler Ro, now clearly a puppet. However it's clear the Federation representatives have an eye on the planet's mineral wealth only and are prepared to outright invade the second they need to, especially as Ro is beginning to have doubts. It's actually a decent plot for a one-off episode with more than the odd dig at British colonial history and other European "missions" to Asia and Africa, and a worthy look at another of the tools of the Federation - we've already seen ruling by military power on Earth and political manoeuvring on Lindor. Now on Horizon it's cultural warfare via the warped Pygmalion scenario of the Federation-educated Ro in his Earth clothes trying to please the Federation's observers.
The Liberator crew basically stumble into the planet, which is a bit of a shame as it would have made a decent proactive mission. It's on their arrival that it falls apart, though. If the discovery of the planet is padding then the away team mission is even more blatant, the crew teleporting down in dribs and drabs to be captured by guards, hitting a low point when Gan is able to briefly resist a tranquilising dart but instead of doing anything useful - like reporting back to Cally and Avon on the ship - chooses to slowly stagger towards his assailant for several long hours before a second dart finishes the job; he was a late addition to the script (initially set to run after "Pressure Point") so maybe the director was annoyed at him? Cally then does basically the same thing but it's nearly worth it as it leaves Avon alone on the ship. There with help from Orac and Zen he calculates that he could survive indefinitely alone unless the ship was attacked by three Federation pursuit ships. Three Federation pursuit ships promptly appear and it's the first real airing for that ironic laugh. In a year's time the end credits would start when he rolled that one out.
Indeed, with his subsequent single-handed rescue of everyone it's hard not to see this as an audition for Avon as a genuine series lead. By this stage there has been feedback from viewers and Season 2 seems to bear out that Avon and Vila were popular with viewers as both would get larger roles. Sally Knyvette had made it clear before filming that she wouldn't be extending her two-year initial contract so it's possible Gareth Thomas had also said the same. If it is an audition it's a success as they're probably the most compelling scenes of the episode and also don't just morph the character into a hero. It's left highly ambiguous if he actually would have left at this point (moreso than it us in a similar situation in Cygnus Alpha, as it's clear that in his own way he likes most if not all of the crew); it's not a reach to suggest he would be happy simply knowing it was possible. And while their friendship has only been slightly developed with hindsight it's interesting to speculate what he would have done if Cally had elected to stay with him. She wouldn't have done but still.
For now though it's still Blake's show and after being freed he deals the coup de grace as Ro and his people rise against the Federation. His scenes as a captive of Ro are interesting as he randomly brings up an old friend of the ruler's who was a "shipmate" on the London after becoming a dissident. It plays well for pricking Ro's conscience but it feels like a hell of an arse-grab. It would be churlish to point out that no such character appeared on Space Fall as we only saw part of the journey but it does seem like a gigantic coincidence (and again might have fitted better if the visit to Horizon was intentional) and almost like Blake's making it up. And what, did Blake just leave Porah on Cygnus Alpha in the cells and never go back? He's lucky Ro has no followup questions really.
Technically the episode isn't bad exactly. Ro is well played by Darien Angadi; his physique isn't quite up to the native outfit Mad Mary cooked up for him but he's nicely conflicted and the choice of an Anglo-Indian actor (with Anglo African Souad Faress as his live interest) works well, being well pitched to bring out the colonial subtext without turning it into "patronise the brown people" clumsiness. William Squire is also great as the Federation Kommissar, a buff old schoolmaster to Ro's face and would-be assassin behind his back. The mining operation and all of Horizon bar the interiors of Ro's palace are entirely represented by a few people in a gorge hitting bits of mud half heartedly with prop pickaxes, while for some reason someone decided this was the moment to release the torsos of Gareth Thomas and Michael Keating on the nation, which neatly encapsulates the show's naive inability to be macho or glamorous. David Jackson, who you'd assume to be in better shape than any of them, gets strapped to a wooden frame with his shirt on for no readily apparent reason while Jenna and Cally are basically reduced to a single unit exchanging a little coalface gal talk with Selma. As Orac is now firmly established as a teleport operator it probably wouldn't have seriously affected the rest of the season if they'd just been left there.
So writing all of this down doesn't make Horizon sound half bad. But it sort of is, and I usually outright skip it on rewatches as it's not important to the plot. Which is harsh as some of the show's best episodes aren't, but the big problem is it's just so boring. The lengthy teleport/capture sequence is the worst offender but there are also endless repetitive interrogation scenes and the episode lacks urgency and intrigue; it's immediately blatant what the Kommissar is planning and that Ro ultimately won't fall into line but it's all span out interminably. But on the balance of it "Horizon" is probably the best of the Prior written episodes. It's just not particularly high praise to say that.