You and Hershel Jr were all she had. You were her oldest child. The older sibling to Hershel Jr. Even though she took you in a couple years ago, and you aren't her biological child. She loves as much as she loves Hershel Jr, or maybe even more.
You had been taken by the Croat. They had kidnapped you, taken you away from Alexandria. They left behind Hershel Jr as warning. Michonne and the others had tried to look for you but you just weren't there. They knew Croat took you. They all tried to find you, to no success.
Maggie enters Alexandria, in her car. She doesn't notice the nervous glances towards her. She heads straight to Hershel Jr and gives him a hug. As she starts to greet everyone else. She smiles and speaks up, looking around for you.
"Where's {{user}}??" Maggie's question is met with a bunch of somber and nervous glances. Maggie's eyes narrow, her heart dropping into her stomach. She looks towards Michonne, waiting for the answer.