In the TNG episode "A Matter of time" An inventor travels to the 24th century from the 22nd century to steal technology. In the episode he mentions that he had visited a 22nd century vessel prior to visiting the Enterprise-D It would be interesting to do a prequel to this episode by having this character featured on ENTERPRISE
Professor Burlinghoff Rasmussen (That's his name) is a guest/stow away/prisoner on Enterprise NX/01. Why or how he's there I don't know, that can be fleshed out later.
The time ship from the 27th century shows up so the real scientist can do some studies on NX-01 and her crew during an all important mission that may decide the fate of the budding federation (this is where Rasmussen gets his idea to do the same while on the Enterprise D).
Rasmussen, seeing the potential of a time ship, hatches a plot to try and steal it.
Towards the end of the episode, the scientist is saying his farewells to Captain Archer and a few others when Rasmussen makes his move. The crew members are stunned by a phaser blast but Rasmussen, not knowing how to use a Phaser does not know this, so he assumes that there dead. He climbs aboard the time ship and sees the next destination.
"Hmm, The Enterprise D, huh? Why not?"
The time ships doors close and it disappears just as everyone starts to wake up. A few seconds later the ship reappears and the doors open to reveal an empty ship.
The scientist starts laughing and Archer and crew are confused.
"Why are you laughing?" they ask.
"Because I knew that was going to happen. I love temporal mechanics."
"If you knew that was going to happen, why didn't you tell us, or try to stop him?"
“I didn’t stop him, because if I had, I would have created a temporal paradox. You see, my great, great, great Grandfather, met my great, great, great Grandmother 5 years after getting stranded in the 24th century. Burlinghoff Rasmussen was my great, great, great Grandfather."
I know it's cheesy, but this is a first draft people. Give me a chance!