The Guardians of Time Omnibus

In the shadows between history and time a secret war is waging-a war where the stakes are the future of humanity.
On one side are the Time Fixers, often called the Time Wreckers by their enemies. They believe fixing past wrongs will pave the way for humanity's salvation.
On the other side are the Time Guardians, who fight for history to remain as it has always has been, believing humankind will find a way to save themselves.
Time Guardian Sigma has pulled together a team of would-be guardians to help him keep history in line; John the pragmatist, feisty Barabal, Alain the inquisitive, and Stanislaus the loyal.
As his team portal through time foiling Time Fixer plots, Sigma is worried they may be winning battles, but they are losing the war-and that's not just because Time Fixer Isolde has been getting inside his head.
Will the Time Guardian's win the war? Will humanity survive the battle? More importantly, will Sigma be there at the end?