When a persistent novice realtor discovers her condescending boss is bankrolling his fancy lifestyle using client escrow funds, she hires an investigator to dig deeper, but he catches on and hires a hit-man to silence her.

Richiev's and Scott's versions work well. Only thing I'd consider changing is giving her a characteristic that suggests an arc for her.

I think this reads a bit better:

When she discovers her boss has embezzled millions, a novice realtor must evade his hitman while searching for the smoking gun that will put him away.

Hi Richiev,
Nicely done, that's a great way to look at it. I had not thought of that angle; it works! thank you! 'Steeldownunder

"When her boss hires a hitman after she discovers he's embezzled millions, a novice realtor, must survive the assassination attempts while searching for the smoking gun that will put her boss away."