This Story is Too Smart For Me

I woke up this morning with a great idea for a time-travel thriller. (Ran it past hubs, who is totally willing to tell me when my ideas suck or are mediocre, and he confirmed that this is indeed a exciting idea.) The problem is that I'm the type of writer who thinks I need five generations of explanation for why my MC owns a dog, so trying to plot and come up with adequate quantum and character background for a time-travel thriller is literally giving me heart palpitations and a headache.