The official CBS synopsis follows:
The Millers stars Will Arnett as Nathan Miller, a recently divorced local roving news reporter looking forward to living the singles’ life until his parents’ marital problems unexpectedly derail his plans. Carol and Tom, separated and planning a divorce after 43 years of marriage, shock their adult children when they each move back in with one of them. Meddlesome Carol moves in with Nathan and sticks her nose in all his affairs, often the most embarrassing third wheel ever to Nathan and Ray, his best friend and cameraman, when they hit the town. Absent-minded Tom imposes on Nathan’s sister, Debbie, her husband, Adam, and their daughter, Mikayla, where he accidently – and regularly – destroys things within the house. Nathan and Debbie quickly realize that to get their parents out of their respective homes, they have to teach them some newfound independence. Soon, with a lot of handholding and a lot more calamity, both parents are discovering the merits to going life solo. Carol learns to relinquish some control of her kids’ lives, while Tom becomes more self-reliant, and both parents even hit the dating scene again. Nathan and Debbie’s efforts are rewarded when Carol decides to leave Nathan’s to strike out on her own. It’s one parent out of the house with one more to go, but for right now – they’re still one big, happily divorced family.