wheel within a wheel

— The fact is, there’s something I rather wanted to call to your attention. You don’t know it, but for private and personal reasons I particularly want to hold this Tiny Tots job for a year. There are wheels within wheels. It’s a sort of bet, as a matter of fact. Have you ever met a girl called Gertrude Butterwick?… However, it’s a long story and I won’t bother you with it now. But you can take it from me that there definitely are wheels within wheels and unless I continue in your employment, till somewhere around the middle of next June, my life will be a blank and all my hopes and dreams shattered.