Darwin is an interesting city on it's own. But it hides secrets, one being that a bus, identical to all the other buses in the city, is a 4th dimensional wormhole. The wormhole transports passengers to different points and places in time: Elizabethan England, the Roman Empire, the American Civil War. But not everyone can handle the surge of energy and sickness from the transportation.
One day, Courtney Green is having an average morning and hops on the right bus but something is different about it. First, she is the only passenger and second she knows that the bus driver is never the one to drive her bus. But when she sits down in a seat, she falls straight through it, a WOMPH swallowing her and the next thing she knows is that she's in 1930's Melbourne, the famous DEAD horse Phar lap winning his next race.
After a few more unexpected trips on the Bus, things start to go wrong: the television isn't invented, Princess Diana survives, Elvis dies sooner then he should. The Present isn't effected immediately but then the changes begin to escalate, changing things that shouldn't be changed.