This recommendation is for the whole series. The Blackwell series are a bunch of charming adventure games about a woman that discover she's actually a spirit medium and with the help of her ghostly assistant is destined to help souls cross to the afterlife. What really makes the games stand out is the writing and characters. The characters are likable and develop over the course of the series, biggest example being the protagonist, Rosa, who starts off as goony social ♥♥♥♥♥♥ but as she eventually accepts her family's calling she becomes far more confident and outgoing. The plots for the games make for some real solid supernatural mystery stories and they even take pages from New York City's history books and actually add some lesser known real people from the city's past into the plot. If you like adventure games definitely check these out, especially because the fifth games isn't too far away

I also really recommend Primordia and Resonance, which the developer, Wadjet Eye, help publish. I'd make separate recommendations for them, but I own them on GOG so I can't.

Surprisingly enough, this game is really great. It has a creative story and gameplay, amazing voice acting, and is a pretty good challenge for fans of point and click games.

Street psychics. Their blinking neon signs are everywhere, promising love and wealth and happiness. They make a fortune preying on the gullible and milking them dry. So when these victims begin dying and leaving confused spirits behind, it can only take a genuine psychic (and her wayward spirit guide) to clean up the mess.

From seedy downtown nightclubs to penthouse apartments to a luxury yacht on the Hudson River, Rosa and Joey will unearth the truth about the underground world of street psychics. Including some secrets that Joey would rather be left buried.

Excellent. I liked Unbound and Convergence more, but this one is still very well written. Can't wait for Epiphany!

I purchased Blackwell Deception as part of the Indie Royale Bundle and to be honest, I didn't know the game beforehand. It's an old school Point and Click graphic adventure, a genre that's lacking nowadays. No need to say it far exceeded my expectations. I hadn't played a P n' C Adventure this good since the Chzo Mythos collection by Ben "Yahtzee" Croshaw. Surely there are other great recent games like the Secret of Monkey Island HD remakes, Sam & Max: The Devil's Playhouse or Hector: Badge of Carnage but they're nothing new. On the other hand, Blackwell Deception is a breeze of fresh air. If I had to describe it I'd say it is a mixture between The Secret of Monkey Island (the boat segment is clearly inspired by the Pirate LeChuck), Maniac Mansion (the supernatural part of the game), Broken Sword (the ambience) and Beneath a Steel Sky (the gadgets Rosa uses, the disco scenario).
The characters are well built and the side dialogues make you know them better if you give the effort. By the end of the game you will really care about what happens to the protagonists (hint on a sequel) .
The puzzles are inventive and well thought-out even though I would have liked to see more item combinations. The "switch character" system can become a little confusing in the not so obvious bits because you'll need to analyze the effect Rosangela and her "spiritual guide" have in each single object to figure out a solution. There's one particular puzzle where you'll need to click the same object for an indetermined amount of times until you succeed, it's kind of random so you might get stuck in that part for some minutes, but it's really nothing serious.
The soundtrack is excellent, the trumpet songs reminded me of Dire Straits final studio album On Every Street.
The game has some replay value, you will probably miss 2 achievements during the first playthrough and then you still have the commentary mode to finish.
I got BD for about 4€ with 3 other games (AVSEQ, Oil Rush and To The Moon) so I consider it was a hell of a deal. Unfortunately I started playing the Blackwell saga from the fourth chapter so I didn't know much about characters' backgrounds/side stories but that's not the game's fault.
I've bought The Blackwell Bundle from Steam since then. I'd recommend this saga to any Graphic Adventure enthusiast