The first part of the adventure- the investigation- was thoroughly enjoyable. My players are fairly savvy, so they got through without much trouble, discovering and following each clue appropriately. The adventure has pre-written hooks to use in case your players get stuck. I didn't need to use these but it was good to know they were there in case I did.
My one complaint about the investigation is that, at one point, it expects the party to use a locate object spell to find the second of a matched set of earrings (one of the clues in the murder mystery). However, the two earrings are too far apart (they're in entirely different districts), way out of the range of the spell, at least at the caster level they had available. Because the adventure explicitly intended for this method to work, I simply decided the second earring was much closer. Otherwise, the investigation was great.
The clues led the party to their first encounter, which was possibly one of the most difficult, but recall that my party started one level lower than the intended level. The fight was against a rakshasa, CR 10. It scared them for a while with its lightning bolts and awesome defenses, but they were eventually able to overwhelm and defeat it.
The next encounters, at the silk mill, had me (and them) worried for a while, because they decided to go in "commando style" through both entrances at once, thus activating multiple encounters! They managed to use some clever magic to trick their foes and make the encounter more manageable. Faerie fire did the trick against the invisible dark naga, and the party was able to get up into the rafters to fight the garuda face-to-face. They were smart enough not to fight it in the open, and it was forced to enter in order to defend the mill.
The next encounter against the disguised were-tiger was made simple by the paladin's detect evil ability. It wasn't about to fool them. No, the paladin wasn't simply casting detection on every single enemy. They noticed something was amiss when they started to talk religion with the supposed keeper of the shrine, who, it turns out, knows nothing about religion. This encounter was a cake-walk.
By the time they reached the village, they were pretty suspicious, and our ranger/rogue did some scouting and discovered some scheming cultists. This encounter was very easy. The following encounter against the variant ghost and zombies was also leveled low by our paladin's channel energy ability.
The group triggered the symbol of pain spell at the temple entrance, but they simply waited an hour to let it wear off. The rogue was able to disable the glyph of warding, preventing the cultists from having any warning of their arrival.
They made short work of the cultists in the initial chamber, preventing any from escaping to warn the masters. They proceeded to the shrine and fought the shrine guardian, a beatific one, who gave them some trouble by disarming the fighter and paladin, but was eventually worn down.
Next up was Deepti, the flaming-chakram-pillar boss. She had them worried, until the witch managed to hex her saving throws (-4 penalty) and then cast moonstruck, forcing Deepti to approach the party and attack with natural weapons. This fight would have been much more challenging if she'd managed to fight from atop the pillars, but their clever use of magic paid off. One of the players also had the idea that a wizard could simply use shatter or stone shape to prevent Deepti's movement on the pillars or cause a fall to the pit below.
Next up was the hardest encounter of the adventure against Ikrimah, who knows the party is coming thanks to his magic and is able to buff himself significantly. He almost killed two of the characters, but they slowly whittled away at his defensive magic and defeated him. Faerie fire negated several of his defenses, including his contingency invisibility escape plan, so the fight basically boiled down to healing through his damage and beating him down.
The last encounter was awesome. The writer clearly intended for a big showdown here, with the surviving cultists and masters all fighting the party, but there were no surviving cultists except the final master! Not only that, but she had absolutely no warning that the party was in the temple. She started offering her challenge of a one-on-one duel (as written in the adventure), but our rogue decided it was time to end things. She got a shot off in the surprise round, won initiative, and got a full attack, hitting multiple times with her magical shocking gravity bow-imbued sneak-attacking cat's grace-guided arrows. The boss dropped to -19 hp in less than one round. Even if the boss had been aware of them and fully buffed, she is the weakest of the masters and would not have posed much of a challenge without any of the others at her side.
With that, the cult was defeated, and the adventurers returned to the city to seek their reward. They are already planning to seek out other cells of the cult in the surrounding area, but those adventures fall outside the contents of this module and this review.