It can be very hard for a GM to surprise the players in a Call of Cthulu game. After all paranoia is the name of the game. (Actually, Paranoia is the name of a different game, but you know what I mean.) The whole point of most Call of Cthulu games is that there are dangers hiding just beneath the surface that are just waiting to devour the characters’ bodies, souls or sanities. Trying to find surprises before they happen and find some way to avoid them is vital for any character in a Call of Cthulu campaign. Nonetheless, the Call of Cthulu adventure Raising Up does a good job of throwing a curve at the characters at the end of the story.
In truth, Raising Up is not a single adventure but rather a short campaign of 5 interrelated adventures. These adventures do not have a theme but rather a single linking feature and a clever GM could easily downplay this aspect so that the players do not realize that the adventures are related or that there is anything significant about the link that unites them. For that matter, a GM could just as easily use one or two of the adventures in their own game without feeling constrained to play through the entire campaign.
Each individual adventure in the mini-campaign also does a good job of keeping the characters off balance without depending on the overarching uncertainty of the game. None of the adventures feature straightforward problems, but each one require the characters to delve deeper and even pay attention to clues that are not obvious.
The characters are not the only ones who are kept in the dark through the course of this mini-campaing. Effort is made to keep the players off balance as well. They do this by ensuring that the creatures and spells that are used as the opposition are new to the game. These new monsters are just as horrendous as anyone would expect in a Call of Cthulu game. They have the weird, unsettling feel of the Mythos and could be easily integrated in an ongoing campaign, assuming any of the characters survive the adventure.
The adventures escalate as the campaign continues, growing steadily more difficult, dangerous and deadly. The first adventure is not much more than clearing a monster and recovering a bit of treasure, but it does not take very long before the characters are exploring a lost pyramid full of ancient (but not eternal) evil. By the end of the story, there are all too many times when it seems likely that at least one of the characters is going to die, though the threat of insanity in the story seems low of a Call of Cthulu game.
Call of Cthulu is only partially an investigative game and the designers of this series have kept that in mind. There is little chance that the characters are not going to be able to pick up the clues necessary to follow the plot. For that matter, the final mystery is not hidden too deeply. The final betrayal is nicely veiled, but the story is tilted so that it is not unlikely that the players are going to figure out the twist before the final reveal.
Raising Up can make a nice introduction to a group of characters who are just getting involved in the unknown world of a Call of Cthulu game. There is even an instrumental NPC character that can serve as a mentor or guide to the party as they start to learn about the things man was not meant to know. Just as easily, this mini-campaign could be slotted into an ongoing, larger story as lasting plot. In either case, the adventures would best be used by scattering them throughout other adventures, bringing the characters into this ongoing story and moving them into other stories from time to time without running straight through it.