Another quest I vaguely remember, and another entry in the long-running Mahjarrat series. When I was a kid I remember siding with Hazeel, though I don't remember why, so I'm going to do it the other way this time.
Roleplaying sidenote, I've decided that Twoie is a Saradominist at this point, because basically everyone in Gielinor is a Saradominist in the Fifth Age. Her allegiance may change as we move forward, but that's where I'm starting. So she opposes Hazeel because he's a big old Zamorakian meany-pants 
.
I also faintly remember a puzzle involving the underground river and the wheels that are dotted around the southern wall of Ardougne. That seems tough, but then that's what I said about Clock Tower. Let's see what happens.
Ooh, you're going to be fun to deal with, I can just tell. Anyway, Sir C sends me to a cave south of his mansion, which I actually already found thanks to my debacle in Monk's Friend. Clivet is more talkative now that I have a reason to be there, though, and he fills me in on the history:
Well, a version of the history, anyway. As a Saradominist this "oppressing Zamorakians" stuff sounds like music to Twoie's ears, and I'm swiftly introduced to the sewer puzzle I mentioned at the start. Alas I can't use the raft just yet, because the current is wrong, so I'm off to figure out what the hell to do. I go back to Ceril for help, but he's a bit preoccupied by my mention of Hazeel:
Yep, I knew you'd be a treat.
Lacking any better direction, I do what I knew I needed to do anyway and go check out the things identified as "sewer valves". The first one I find is labelled "2 of 5", so I go off in search of "1 of 5" and turn it. That gets me progress, anyway, but I have more to do. I'm not getting a lot of feedback here, so let's try turning "2 of 5". That got me a bit further, so back to the valves.
I'll spare you the whole story of me solving the puzzle, but basically I just had to turn each of the five valves once. I seem to remember it being more complicated, but whatever. That gets me to the cultist's hideout, and they're not happy to see me: the first one I talk to has the gall to attack me! Luckily, despite having 1000 health, he's weak to arrows (which I happen to have equipped), so I swiftly dispatch him. I decide to avoid dealing with the other cultists, and head straight to their leader. He's only level 9, despite his underlings being level 28, so he's easy to take care of.
Minor annoyance, though: he respawns instantly on death, right on top of the armour his predecessor dropped. So I need to right-click, which is a pain when you've got a trackpad. But I've got the armour, and I'm back to Ceril for my reward.
Scabby cheapskate. Quest...complete?
Not quite, which is a fun gag. I still need to prove that Butler Jones is in league with the cult (subtly hinted by Ceril's dialogue - good design again!). I figure that whatever I need is going to be in the manor, so I hunt around looking for interactable things. First place I look is the wardrobe in the master bedroom, and sure enough the nitwit has left his Mark of Hazeel right next to a bottle of poison. Why are criminals so dumb?
Quest complete.
Overall not a terrible quest. The sewer valve puzzle was far less complicated than I remember it being, and is possibly too easy, though it is a novice quest. I also liked the second half of the quest on the "good" path (which is new to me, I never saw that as a kid). The fake-out "quest complete" dialog was a nice little gag, though the location of the poison didn't make any sense to me; why would the butler store his evil things in his master's bedroom? I'd have expected to find it in his own room, or in the kitchen at least.
Out of curiosity I checked the wiki to see if there were any other ways to solve it (for instance, maybe the poison was always in the first place you looked?) but no, it's in the master wardrobe. That seems like an odd narrative choice, but whatever. Though the wiki did say that the sewer puzzle was made significantly easier with the release of Carnillean Rising, so that makes me feel a little better about that part.