We're currently playing through Mummy's Mask, and are on Adventure #3, and the party have been researching through the libraries. Last session, they got 2/3 of the way through the Dark Depository, ending the session by getting the transcript of the interrogations of the creators of the Mask, and finding out the Heart was taken to Sothis.
... so naturally they ended the session wanting to go to Sothis to look for the heart, unaware the heart has possessed the now-leader of the Cult of the Forgotten Pharoah, and thus in the Parched Dunes.
This has left me wondering where to go next session, but there's a complication: one of our players is leaving next session, and two new players are joining the session after next, so either things need to wrap up for that player next session and a good jumping point needs to be available in two sessions time, or I ask if the old player minds holding on for a bit and the others join a little later.
So with that in mind, plans for the next session could be:
GO OFF BOOK: I simply encourage the players to head to Sothis; next session gives leaving player the chance to stay behind, and new players join either in Sothis or on the way to Sothis. I have to create my own sub-quest in Sothis, as the players learn what exactly happened to the heart and how it is in the Parched Dunes (possibly working out a way to let them seek out the tomb at the end of Book 3, possibly for different reasons).
Downside of this is I know absolutely nothing about Sothis! But I suppose there's a whole book on the city, so I might just have to pick it up.
2. SOFT RAILROAD: I inform the players through plot that the heart is with the Cult of the Forgotten Pharoah. Probably the best way to do this is to have cultists enter the Dark Depository start of next session, and have them openly talk about reuniting the ka and the ib for their mistress. They could even talk about Chisisek's tomb and their operations there, giving the players further direction to head into the desert and seek out the end of Book 3. Would mean realistically I'd want to ask to delay old player leaving and new players joining, since it'll take a few more sessions to finish up events in Tephu (but the players would get to find all the gritty things there like the live mummifications, and the fourth library).
3. HARD RAILROAD: Someone - probably from the Temple of Nethys in Sothis - mysteriously arrives in town, tells the party they've found out about their investigation, actively informs them of events in Sothis and that the Cult of the Forgotten Pharoah, and tells them they know the cult have made camp in the desert. A bit agency removing (I'm literally telling the party to go to the desert), but would pretty directly point the party into the Dunes for the whole strech before Book 5; and the out-of-game schedule still works fine (old player leaves when we agreed, new players come in when I said they could).
Thoughts?
Naturally going off book sounds best in principle, would just need to think of something interesting to happen in the capital. Had we not had the player switcheroo, I'd probably be include to go with the soft railroad, just so the players could see the rest of that section of the book, but I guess none of it is strictly necessary for the story and what is can be replaced with a stronger mystery sounding the heart.