The Mound: Omen of Cthulhu Guide | How to Complete the Portal Mission

The Portal Mission in The Mound: Omen of Cthulhu is confusing because the objective does not work like a normal treasure Contract. The Ox-Wagon is unavailable, the objective requires a chalice interaction at the Portal, and the corrupted ground can kill you quickly after the ritual begins. The safest method is to travel light, identify the escape route first, and leave immediately after completing the interaction.

Prepare Without the Ox-Wagon

When the expedition begins, the Ox-Wagon may remain suspended beside the Tempestad. This is part of the Portal Mission rather than a broken Contract. Carry only the equipment needed to survive the route because you cannot depend on the wagon’s storage, mobile shelter, or normal return function.

Carry the Chalice to the Portal

Follow the mission route until you reach the Portal area and locate the chalice connected to the objective. Keep your hands free for the item and avoid unnecessary treasure detours. Before approaching the Portal, look back along the route and choose a clear direction for your escape.

Throw the Chalice Into the Portal

Move close enough to reach the Portal, then throw the chalice into it. Do not remain in the ritual area waiting for another prompt. The interaction activates dangerous purple corruption across the ground, and standing in or crossing the wrong section can end the run immediately.

Turn Around and Escape Immediately

As soon as the chalice enters the Portal, turn around and sprint along the route you checked earlier. Keep moving, avoid the spreading purple zones, and do not stop to fight unless an enemy completely blocks the path. Once the objective registers, reach the expedition exit to complete the Portal Mission.

Throw the chalice into the Portal and immediately sprint away from the corrupted ritual area to survive and complete the mission.

FAQ

Q. What do you do with the chalice in the Portal Mission?

A. Carry the chalice to the Portal and throw it inside to activate and complete the main objective.

Q. Can the Portal Mission be completed solo?

A. Yes, but solo completion is unforgiving. Carry a light loadout, avoid optional fights, and memorize the return path before throwing the chalice.