Marge discovers her gift for carpentry but has to use Homer as a front in order to overcome people's predisposed prejudices against women builders. Even though he is completely inept, Homer takes credit for all of Marge's work which causes her to abandon him just before he lands a job rebuilding a historic Springfield rollercoaster. When Homer's life is in danger while taking the rebuilt coaster's maiden voyage, Marge arrives and the couple works out their differences just before the Homer careens off the coaster. Meanwhile, Bart uses Skinner's peanut allergy to force the Principal to do his bidding.