Think Men in Black and that's kind of what you've got with the SPI Files series. I didn't feel book 6 was the strongest as there seemed to be more back story info dumping than previous iterations. Given that though Mak and her team spend their time chasing down buildings that keep disappearing and reappearing where they're not supposed to courtesy of some off-world enemies who've decided to form an evil cabal in an attempt to bring down the SPI.