"Straying" is episode 145 of the Berserk manga.
Guts kills two Hunters in four quick swings of his sword, greatly impressing the surrounding crowd and terrifying the remaining Hunters. Suddenly realizing they can fight back against these oppressive men, the crowd drives the Hunters away using rocks and glaring looks.
Now safe from harm, Luca walks up to Guts and tells him she knows a Branded woman. Finally finding his first link to recovering Casca, he grabs Luca's shoulders and demands she lead the way to her. Luca doesn't move right away, instead sizing Guts up. It's only upon seeing a Brand identical to Casca's on Guts' neck does she grab his hand and lead him to his lost lover. The scene is watched from a distance by the mysterious being.
Nina, who is the only girl besides Casca still in the tent, asks her to use her witchcraft to save Luca and the other girls. Casca pays her no mind, finding objects around the tent to amuse herself with. A wave of panic flows through Nina, who suspects that Luca has been arrested and that the Hunters will come for her next. She decides she must run away, and she wants to take Casca with her.
Luca runs back to the tent with Guts close behind. He swears to find Casca and bring her home safely. As they run, Luca turns her head and asks Guts what his relationship is to Casca, but before he can answer, she comes to her own conclusions and drops the matter. They arrive at the tent. Guts is the first person to enter it, but he finds it empty. Luca at first suspects that the Hunters kidnapped Casca and Nina, but the tent is in meticulous condition, and she realizes that Nina must have run away and taken Casca with her.
Nina leads Casca away from the camps, coughing up blood along the away. They come across the group of heretics Nina once associated with, who have come to abduct Casca.
Luca, Guts, the other prostitutes and Isidro have all split up in search of Casca. As Isidro - along with Puck - wanders around camp, several refugees call attention to the elf sitting atop the boy's head. This baffles Puck, who is used to large crowds being unable to see him. As they walk along, Isidro reveals that he follows Guts around to learn his moves, either by being taught or by stealing them outright. It is at this moment when they spot Casca being taken away by the heretics in the distance. Judging that it would be more prudent to follow them rather than inform Guts of what he's seen, Isidro and Puck follow the kidnappers discreetly.
Guts, Luca and the prostitutes all converge at their meeting point, but none of them have managed to locate Casca. Luca says that she hasn't heard from Isidro in a while and advises that they wait for the boy to return. Guts is too anxious to sit around and goes off alone to search for Casca around the camps again.
Characters in Order of Appearance