Holideath Resort (Book Two of the 'Zombino' series)

Wes, Nelson, Susan and Stuart are still trying to escape their forsaken, monster-infested office block. It isn't easy. They've been separated into two groups and left for dead in the middle of nowhere, controlled by a man who doesn't care whether they live or die...so long as he can collect his data.

Holideath Resort is Book Two of the Zombino series, and is classed as a novella at 34,000 words.