This was a very well done start to what will definitely be a fascinating and exciting series.
Lockwood and Lucy are the top agents in a paranormal/psychological investigation agency. They are ghost-hunters. Ghosts are a plague, an epidemic in London and it's up to young people like Lockwood's team to take them out, help them to the other side, and protect people.
The author knows what he's doing, and combines great writing skills with well-rounded characters and an interesting almost-dystopic-Britain setting. The language is quirky and complex, with just the right amount of paranormal, ghost-hunting jargon. The protagonists are a perfect pair of mis-matched teens, always at each others throats but ready to take a hit for each other, too. The secondary characters are interesting enough to stand alone. The ghost-infested city of London is altogether creepy and tantalizing.
The cases that Lockwood and his team take on - both to help people and to make money to keep their agency running - are always creepy and compelling page-turners. The mysteries seem a little predictable, but then hit you with a twist. Lucy's point of view keeps the repetition of the case->adventure->solved->basecamp routine from becoming dull.
Think Harry Potter, Sherlock, and Ghostbusters all mashed together: that's Lockwood & Co. It's a great new series that middle schoolers, teens, and adults will love.