I have a very silly AU headcanon. It involves Cisco as a high-profile businessman or politician, and Harry as a hitman. No, not hired to kill Cisco. Another hitman, Hunter Zolomon, has been hired to kill Cisco. Harry and Zolomon have a bitter rivalry and Harry dislikes Zolomon so much he’s decided he's going to sabotage Zolomon’s next job.
Harry starts protecting Cisco from afar - tipping off police and security personnel, creating other faux threats that juice up security and change Cisco's schedule so that Zolomon can’t plan or execute his hit. Zolomon is furious. He continues to pursue the mark and Harry has to watch Cisco more closely to protect him. During his constant surveillance he notices that Cisco is brilliant, kind, and good at his job. It’s a shame there’s a hit out on him.
Zolomon is getting more and more determined. He arranges a trap for Cisco by setting up a false meeting with one of his colleagues. Harry finds out too late to tip off security, and in desperation he kidnaps Cisco en route to the meeting. Cisco’s scared but full of bravery and sass and he’s downright offended when Harry explains the situation.
“Oh my god, you’re saving my life because you’re a petty asshole?!”
“...Would you rather I let you die?”
Harry, for his part, has reluctantly grown to like Cisco. Protecting him has become more than just messing with Zolomon’s 100% hit record. And Zolomon is definitely still out to finish the job! They have a dangerous cat-and-mouse game ahead, and Harry is the only one who can keep Cisco safe...