Mia invites Maddie and Ben to meet Casey, and they think they're meeting just another in a long line of boyfriends. But Maddie realizes how serious things actually are when Mia and Casey excitedly announce that they're engaged. Surprised by the news, Maddie feels like her little sister has leapfrogged over her -- jumping ahead of her in some major, life-changing way -- and sees the light it shines on her own life choices. But reluctant to be a negative voice, she resolves to be supportive and let her parents, the critical Vicky and Joel, be the ones to object when the time comes. But when Mia tells them that she and Casey are getting married, Vicky and Joel greet the news with celebration, much to Mia's delight and Maddie's surprise.