Frankie's type-A sister Janet is back, and her "help" is doing more harm than good.
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Tonight, Molly Shannon reprises her role as Patricia Heaton's sister, volunteering to help run the Heck household while Frankie crams for her dental school finals.
Check out a sneak peek of the hilarious episode in the video above!
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The Middle airs Wednesdays at 8 p.m. on ABC.