Last night I dreamed that I was taking tests in high school, and after they were done I was heading out, but I got stopped by this little old lady who asked if I could help get her and her friends to the auditorium. So I ended up walking four little old ladies (the one who stopped me was in a wheelchair; a second was using a walker, the third was slow, and the fourth was spry) around for a while. Turns out that unlike in my actual high school, this one's auditorium was across the street. I got them to the side of the road and then helped the one in the wheelchair across. When I got back I discovered that the spry one had gone missing; when I asked, one of the others said she "went to the bathroom" and just never came back. (I never found her.)
The dream fast forwarded to me getting home (where I grew up, rather than my new apartment) with Tara. After a bit more of a time skip she was heading home and I asked if she was walking, to which she replied "not if you give me a ride..." So I agreed to despite (or more likely, because) of the torrential downpour that had been happening for hours. We slogged through the water (which was flooding) to get to my car. She was able to hop in but I needed to swim a bit. The water was up to my hips at one point.
Rather than taking her home, turns out she'd left something at school so I took her back there. We began walking through the empty building, where I discovered that it was flooded in the basement. We slogged through more and more water and finally made it to a classroom in the basement where music had been playing; turns out she'd left a cassette tape. So she grabbed that and we were able to swim back out (ps it was shady as hell in here) but then this guy showed up and he was some bad guy who basically told me that I had to solve a puzzle or the world would flood.
So I began looking at it but couldn't make heads or tails of it. He said one person could help me and this random girl (I recognized her and knew her, but I can't remember who she was anymore) offered to help. Because I trusted her I said okay, and she picked out this math problem among all the puzzle options. It involved transposing graph lines and she insisted it would be super easy because of some clues that were suddenly written on the blackboard. Before I could say anything, she told the bad guy that was the one we'd be doing (which was terrible because it looked like total gibberish to me, just like all the rest). Through all this the guy had been gloating about trust and betrayals and something he said made me realize that my trust in this girl was misplaced, but it was too late. She'd said which we were doing and he started laughing and when I accused her of betraying me, she just smirked as well and didn't deny it.