Time after Time

You won't believe this, but I'm about to tell you a story that will change the course of history. A story about time travel, secret agents, and paradoxes. It's a story that will start with a chance encounter with a time traveler known as Jack the Ripper, and it will end with the founding of TACO, the Time Acency Chronoclasm Organisation, a powerful agency controlling time travel throughout history.
The second short story tells how I was coerced into joining TACO as an observer on a mission to rescue the Blair witch. It was either that or be slightly dead. Apparently, the Blair witch was also a TACO agent and had been set-up to be almost killed by the good citizens of Blair by BELL, the time travel equivalent of the FBI. They wouldn't tell me what BELL stood for.
The third story, my second time-travel mission, was to make sure the Titanic sank! Over 1,500 died but their deaths saved the lives of millions throughout the timeverses.
The fourth story deals with paradoxes. 1493 wasn't ready for flying machines so Alex Pearin (aka Jack the Ripper) and I traveled to Florence in Tuscany to talk to Leonardo da Vinci about paradoxes and why he shouldn't build the world's first flying machine. Alex and I ended up helping Leonardo complete a flying machine and helping him on its first flight. I also solve a couple of other mysteries and discover I founded BELL.