Can someone please tell me how we can save the Cassie at Don's Mansion?
Talk to Fawn (your condo neighbor) to get it started. Talk to Arlene in the police department to learn about causing a diversion. Talk to the hobos (ignore the first guy) and give them 500 credits, then go to sleep. Talk to Arlene again to learn the hobos are rioting. This much is required to avoid a Game Over.
You can also get help from Sammy, Fawn, and Lin Lin. Not required, but it helps a great deal.