Time traveling is not a new idea, and novel/movie about the concept is quite common too.
But when time traveling involves a larger scale than just one person travels from one year to another year, a lot of changes are interestingly presented.
If the timeline of our universe is messed up, people from different times (more than just two different times) are all 'time traveled' to a single point of time, then there is a interesting interaction. Between people and people, between people and environment, between environment and environment.
What if an old guy goes back 40 years ago, and met his young self?
What if two famous historical figures like Alexander and Genghis Khan met each other? Who will win the battle?
What if a modern day people met with stone age people? What will be the cultural exchange?
What if a patch of tropical forest is time traveled to so many billion years ago that its surrounding environment is desert?
There is a famous scenario.
That is, if I time travel back to thousands years ago, and I kill Cynthya's great-great-great-to the nth-grandmother, then there won't be a person called Cynthya, and so I wont't know Cynthya, and so I won't know Cynthya's great-great-great-to the nth- grandmother, and so how can I know that I want to kill her if I don't know her in the first place.
All these issues are interestingly discussed and expanded in this novel called Time's Eye. Book 1 of the Time Odyssey trilogy.