Your heroine is being chased by a gang of people.
They’re shooting at her. She jumps into her vehicle (This vehicle could be a space ship or a time traveling device, you’re not limited to a car here) and hits the gas. As she’s escaping she notices someone is with her.
It’s too late to turn back, they’re on this adventure together.
Who is in the vehicle with her, why doesn’t she want them there?
Who is chasing her and what happens?