Just another GR refugee. Other than that, I had a stroke in 2004, and read almost anything I can get my hands on, though I have a particular weakness for history, mystery, and historical fiction.
A Gathering of Shadows is the sequel to A Darker Shade of Magic, which I read last year, and enjoyed a good bit.
In that volume, we followed Kell, a magician who works as a royal messenger between the rulers of three Londons. He is the adopted son of the rulers of Red London, where magic flourishes, and sends and receives their messages to the rulers of two other Londons - to George III and his son, the Prince Regent, in Gray London, "our" London, where there is no magic, and to the Dane siblings, rulers of White London, a choked and violent land where magic is rare and whose people will do anything to possess it. In Gray London he met the thief Lila Bard, in his sideline as a smuggler, and together the two of them take down the Danes and save the life of Prince Rhys, Kell's brother.
Now it is four months later, Kell's parents have forgiven one son (Rhys) but are punishing the other (Kell), and the latter is a very unhappy man, while Rhys plans the ceremonies for London's hosting of the Olympics of magic. Meanwhile, Lila Bard has gone to sea and become a privateer, though she'd rather be a pirate. Or a magician, for that matter.
I have to give this book a slightly lower rating, despite the fact that I enjoyed it, for a few reasons. In the first place, it has too many narrators: Kell, Lila, and Rhys in Red London, and also two inhabitants of White London. Five narrators is a lot for one book.
Secondly, it's the second volume of a series, so much of the fun is not fresh discovery. And it ends in a cliffhanger. A very serious cliffhanger. (A Darker Shade of Magic was a contained story.)
Also, is there anything Lila Bard can't do? This is starting to head into "Ayla discovers everything" territory, from the Clan of the Cave Bear novels (I forget their group name - is it "Earth's Children"?).