On the face of it, this is a simple 'Go-Fetch' adventure, with the characters being hired to go and retrieve an item for someone. Nothing's ever quite that simple, though! Starting with some background for the GM, which is very much embedded in Adventureaweek's own campaign world (and quite hard to interpret if you do not subscribe to their website or at least have not read earlier adventures to get an idea of some of the main players), it would be possible to site in your own world if you re-jig the background a bit.
The 'hook' is simple, one particular inhabitant of the characters' base village of Rybalka summons them and asks them to fetch him an item called the Tri-Stone. He doesn't say why, indeed he is acting as an agent for someone else and although he can tell them who he is acting for, he has little idea of why they might want the Tri-Stone anyway. He doesn't know where it is to be found either, but has a 'runestick' carved in ancient runes which gives directions to a 'runestone' that gives the location (in more ancient runes, of course). If anyone in the party is good at linguistics, here's their chance to shine... er, or might if the runestick was actually shown! There's a kind of Rosetta stone, showing how the runes relate to the normal alphabet, and the runestone they are supposed to discover is illustrated nicely - but for the runestick itself, you'll either have to make your own (standard Norse runes are used, so it's quite straightforward to knock up) or just tell them the results on a successful die roll. If nobody has the requisite skills, they can ask the local sage, but there may be unexpected consequences brought about by them talking about their quest. Even once deciphered, it's all a bit cryptic and you will probably end up having to tell them where to go.
Hopefully, the characters will eventually find out where they need to go, and will have to make a wilderness trek to find the runestone... and then decipher that as well! Again, the translation is cryptic although this time a couple of thoughts are given as to how the characters can get guidance as to where to go next. Whilst it all makes for good flavour, it all drags on a bit, and you might want to throw in a wandering monster or two to liven things up!
Once (if?) the characters make their way to the site where they will find the artifact, they face a challenging scramble (the effects of falling off the cliff into an icy lake beneath are well laid out in case someone slips) and a truly novel adventure location to explore. This is where everything ramps up to the expected standard of presentation and detail we've come to expect from Adventureaweek - clear text, vivid descriptions and some neat maps (including one that's 'player friendly'). Exploration should prove exciting and challenging, with traps to negotiate as well as guardians to fight or evade... even if very precise steps are needed to detect or disarm some of the traps. A competent GM will allow for other reasonable efforts.
The item found (and anything else taken that the characters wish, even though they were asked to leave the place undisturbed), there's a set-piece brawl on the way home, one which will present a considerable challenge with a real risk of defeat! Measures are in hand to ensure that the characters survive and get back to Rybalka, whether successfully or not.
There's a neat plot twist at the end, presented for the GM's eyes only I think - it's not clear if you are supposed to read it out or not - but providing scope for future adventure...
The quest itself and in particular the adventure location is the stuff of which legends may be written and songs sung. The introduction of the runes is a neat idea, but suffers somewhat in its execution. This will make a good addition to the ongoing saga of a group of adventurers making their name in and around Rybalka.