A Groph Module will spawn outside the map somewhere near a dragon location. Zombies will not spawn inside the map, but they will spawn outside and attack the Module. Defend it by shooting down below with your weapons and Dragon Strikes. Undead Man Walking can help in defending the module. Do not worry about watching your back.
Once completed and the pod is opened, release the Whelp from the Gauntlet of Siegfried. It will fly towards the pod and retrieve cargo for you to pick up.
Take the cargo and give it to Sophia to complete the challenge.