You go to the fortress where the templars have gathered and you have to fight off a demon boss in the following celebration-of-dumbfuckery way: You start in a Main Hall from which you have two doors - one on the left, one on the right side of the hall. You take one of the doors and you have a dungeon-like area that you have to make your way through via killing all "red templars" in your way, which is how you save three templar officers standing (at pre-determined spots of course) in the dungeon area (it's really a part of the fortress under open sky, but who gives a shit). I should tell you that the last officer's dialogue didn't start the first time I saved him, so I had to reload a savegame to re-save him, and fortunately it worked that time.
Once you're done with that task, you need to take the other door from the main hall, ending up in a courtyard where you have to click on more red templars until they drop, then enter a room, where some spooky signs have been drawn on a wall, serial murderer hideout style (oh my, so spooky), then take a key from that room, use the key to enter a room that's right next to the first one, dear, dear, that was tough, click on some red lyrim inside second room to get a codex entry and party comments of it. Then take your ass back to the Main Hall.
Now the topping of this shit-cake is that every time you exit the Main Hall, you are on a timer. Half the Main Hall is green-fade-magic-blocked by the demon, who keeps spawning red templar baddies inside your part of the Main Hall to pester you. So, as I said, you're on a timer once you leave the main hall, and you have to finish the tasks I described before the timer runs out, or the templars inside the main hall will be killed, in which case I suppose you get a big yellow "Mission failed" sign like in GTA, but that would probably be too fun for DAI.
Two caveats that make this even dumber than it sounds - first, the templars you are supposed to protect are indestructible ingame (same as those you are setting out to "save"), so all this errand made up by an unknown shitbrain and its failure are completely scripted, and second - the timer only serves to make you return back in the Main Hall while you're halfway to completing the officer-saving or lyrium clicking errands, it does not determine when enemies will show up in the main hall! So it doesn't matter if you exit and immediately enter back into the main hall, the red templar enemies will spawn every time, regardless of the timer! It's like they're waiting for you to leave the room to sneak back in.
Once you're done with the mini-fetch-quests, what follows is a grand battle within the Main Hall against... more waves of red templars! Wow! Kill the red templars, and you get a cue from the Chief Good Templar present in the Main Hall that "it's time to end the demon". His, and the other templars' role in the "ending" though amount to zero. It's just your party that has to go out from the Main Hall to some terrace and fight a very dumb 30 000 HP boss who spawns two waves of red templars when he's at half and 1/4 health.
Another brilliant achievement in BioWare quest-writing retardedness is that you have to go through all that I described without ever renewing your healing potions, which in my case meant that when I finally reached the final battle I was down to 2 health (for all the party) and a couple of regen potions (per character), which made it unthinkable to kill the demon on Hard difficulty, as I had been trying to play so far. So, the moral of the whole story is that what you should be saving is not templars but your own health potions. Great job, dumbasses!
After getting my ass kicked, I rolled the difficulty back to Retard and beat the boss. It would have ended here if this was simply a shitty game, but let's not forget that we are dealing with more than that - this is a BioWare game, which means you have "meaningful choices"...
As soon as I'd killed the demon the doors to the terrace busted open and a group composed of Chief Good Tepmlar and some mute and unnamed colleagues of his came out and pledged their support for the Inquisition's efforts to close the Breach. Gee, thanks, asswipes. I had a choice between accepting them to work alongside the Inquisition or incorporate them into the inquisition. I don't need to tell you I chose the latter, which strangely pissed off a few of my companions and advisors somewhat. When I got back to the base, Cullen whined that this should have been the Inquisition's decision, not my personal one. I ignored him, changing the subject of the conversation to how we'll need more lyrium at the base to accommodate the templars who were on their way. Then out of nowhere, in a puff of incloosive smoke, the emo with the hat popped up right upon the table and it took us a whole two lines of "witty dialogue™" to have him get off the table and disappear again.