Time Before Time Vol. 1

Summary: Far in the future, humankind has made the world so toxic that time travel to the past has become the refuge of the rich and the desperate. For a price, you can be smuggled back in time to an era where you can safely live out the rest of your days. If you can't afford the price of passage, you can work off your debt as a smuggler risking radiation poisoning, running into rival gangs of time travelers, and having your time machine stolen by yourself from another moment in time.