M1: Into the Maelstrom
M1: Into the Maelstrom is the Moldvay-Mentzer foray into Epic play, here the "Master's" line. The Heard family is credited with this one, Bruce and Beatrice. Homer of Halicarnassus isn't credited but he's dead.
There already was a M-series, for single-player at Basic level. Blizzard Pass. They just went and redid the series here. Who knows why; they didn't do Companion as another C-series.
TSR are still not done with Norwold so that's the backdrop: the baron Norlan of some fellow Alphatian island gets a boner, and makes his move on an Alphatian princess. In the meantime an ultimatum in Norlan's name has gone to Norwold, along with a vast magic plague. The party must set sail to Qeodhar, with a fleet, to deal with the problem. What does the ultimatum even say? Don't know!
It's Helen of Troy as MacGuffin ... sort of. The module starts out unable to make up its mind if Norlan is the baddie, about to switch teams to Thyatis; or the Immortals' patsy. The only reason Norwold is involved with this whole affair is plot: to get a Norwold-based party onto the oceans.
Once Norlan is confronted the goddess Vanya drags the party's whole fleet into chapter 2, The Odyssey... in Spaaace. And what would Homer be without the Homeric gods I mean, Immortals: Koryis, Vanya, Alphaks. The party's actions deliver Victory Points to the gods. Koryis wants peace. Vanya wants displays of valour. Alphaks, the real baddie here, wants to kill you.
If the players didn't lynch their DM for running an adventure thus far confused and derivative by stages, Chapter 3 puts the party onto an original quest, to get their fleet through Star Kingdoms in a Cold War. (It was the 1980s.) They are Belthar, Gammar, and Delthar... implying an "Alphar" somewhere/when. The party's fleet upends the balance of power between the three. Once the party gets through that, back in their own world the Heards unleash a navy of deadites at their already-battered fleet, which the authors know in advance will likely finish it off. The party's wisest move is to ask the fleet's captains to put them on a skiff, and dare the DM to go through with this dick move.
The rest of the chapter, and the adventure, is an assault on Alphaks' base in this world. It's a volcano. Of course.
The module introduces a War Machine adaptation for the oceans - so that's valuable for the other C-M modules, not least CM1: Test of the Warlords, maybe even X10 if that party has the ballz to hit Ylaruam from the east. Also introduced are the Demons - the Roaring one, your Type VI standard LOLrog. The Expert-level demons in X2: Castle Amber are hereby abandoned: Demons are Master-level from now on, which the Immortals rules will formalise.
There's a sequel. Skip Williams, M2: Vengeance of Alphaks. It's a collection of minor encounters, some voluntary; and has Alphaks fucking with the PC's dominions. At the end Thyatis invades ... again. Recommend to loot M2's encounters as prequel to M1.