Undertale Hateful Eight: Story of Men vs Monsters

Imagine a scenario in which the six fallen people who kicked the bucket before Frisk never passed on and rather joined Frisk on their voyage through the Underground. Everything appears to be great... beside Frisk. For what reason would they say they are truly in this course of events? What do they need? Join the other six as they attempt to find out about 'the eighth human', why everything is so weird and how to get away from the underground.