Gare Marx has been a PI for all of five minutes when he discovers he sucks at it. The mob wants money he never borrowed, he's suspected of murdering someone he hasn't met, and he's hired to find a woman who may be involved in some extremely shady business. That, and his secretary is an amoral jiu jitsu-loving sociopath.
With only hours before his life is ended in multiple (possibly concurrent) horrible ways, he has to dig up the courage and/or resources to solve the case(s), before the cases "solve" him.
Interesting side note: when asked about money you dont have, it is generally a bad idea to say "I dont have it", as opposed to "I will have to find out for you". Saying "I dont have it" implies you had it, but have since un-had it. This is seen as an admission of guilt to people who (for the sake of argument) wear leather sports jackets, and quite often results in personal injury.