Sid McDaniel is a private investigator.
He is a very specialized "modern private eye", as he puts its, "a dude who has nabbed corporate moles pilfering millions and who has stopped international hacking syndicates financed by the Chinese government or by the Russians". He makes it a point to do into any assignment in disguise so as to not let his true identity ever get known so "when I was done with a job I needed to be able to disappear, so that, you know, I could go on living. I needed to be able to toss away the fake person as I seamlessly became someone else". The reason for the subtefuge is pretty simple to understand; the people he is asked to investigate are often extremely powerful and even more so deadly and creating another dead body - his - floating in a river somewhere would not bother them at all.
As we meet him, he is a month into a job and shows up for work at his target's place of business every day disguised as "a frumpy, pasty, middle-aged nobody in cheap, common clothes" complete with a soft sweaty blubbery fat-suit that is also bulletproof. He is very careful in creating a false identity that is meticulously backtraced with a social security number, bank accounts, and even a very modest social media presence. McDaniel is very good at his job. Which is why he is stunned and not a little demoralized to have his entire life's history ripped open and sent to everyone he had ever known and any client he has ever worked for. This included every group he had ever stymied - all those very powerful, very deadly people I mentioned earlier.
We learn early on that McDaniel was raised by a widowed father from the time he was 12 and his father, though successful on Wall Street as a broker had major trouble with alcohol. As a result, McDaniel learned from his teen years to fend for himself and to do things his own way. He taught himself programming even as he studied accounting and while his grades were good enough to get into MIT, he knew after two years that he has learned as much as he needed there to do what he wanted. From then on, he had earned a very good living and an excellent reputation at his new line of work. That meant more than once skirting a few laws and regulations and possibly ethics - just a tad here and there - but nothing that would really upset anyone enough to come after him. Until they do.
Now McDaniel must use all his experience and skillsets to take on those who have chosen to take him on.