Maggie is walking for the first time!
The story here is that Homer got home from work and walked in the frontdoor seeing Maggie by the stairs playing with some toys. While Homer hang his jacket he saw in his sidesight that Maggie was trying to stand up. Something she had never done before. He looked at her while she stood on her feet and then took her first step! In big shock and with a hugh smile on his face he called on Marge to see this beautiful moment. She dropped what she did and went out to the hall. She gasped when she saw Maggie half away from her daddy while Homer had bent down and had opened arms to take her. They were so proud of her!