They decided to search in Mewni's wild areas, being that's where Ludo first was sent to, when Star shoved him in the portal. River, Moon and Marco searched for her, Moon carrying a sword to protect Marco and his wife, as the monsters that Ludo had around the area, were still around and swarming the place. They came at night to look for her, as that's when they are not there, and hopefully, not run into them. Eventually, after hours of searching, they decided to give up, and just go home.
Moon tried to comfort Marco. "It's not your fault, boy. I miss her too. She's my daughter, I love her more than anything else in my life, except for my wife, of course. We're going to get her back...".
Marco appreciated the comfort. "Get some sleep you two. This month's going to be a rough one."
Meanwhile, Star herself, was going through the planet, and accessed the desk. She found shirts for her to wear, a pocket knife, a first-aid kit, some food.
"Well, if this anything like all those survival movies, me and Marco watched... this isn't going to be easy. But, I'm a butterfly, I don't give up."
So, she went into the unknown, moving from her bed, hoping to find signs of life.