Spiral

Spiral is the fifth and penultimate book of the Tunnels series, which is written by Roderick Gordon and Brian Williams. It was published by Chicken House on September 1, 2011. It has four books preceding it, entitled Tunnels, Deeper, Freefall, and Closer, and has none succeeding it so far. The book Spiral chronicles Will Burrows and his friends -- including loyal Chester, resourceful Elliot, wily Drake, and newly empowered Mrs. Burrows -- held up at a mysterious estate owned by Drake's military veteran father, trying to figure out what to do next in their ongoing war against the evil Styx. The killer Dominion virus is no longer No. 1 on the threat list, but it turns out the Styx have something even deadlier on deck. It's called the Phase, and if it's carried out to completion, all of humanity could be washed away in a bloody genocide. As usual, it's up to Will and the gang to eliminate the threat ... if they can.