A tempting offer.

After making their way through The Iron Labyrinth of the 2nd Circle of Hell, the Guardians and their companions were chased into the 3rd circle.

They came out of the winding iron of Mephisto's 2nd circle and immediately found themselves jetted into equally disturbing surroundings. Stretching out in all directions was a vast rocky valley, with a series of craggy hills encircling them at a distance of approximately 500 yards. Above them, the sky was pitch black; all of the local illumination was provided by the occasional crimson bolt of fiery red lightning that tore across the landscape. Unfortunately, according to Mephisto's map they still had great distance before they would reach their quarry Galactus. 

Just as they were about to set out again, they heard a menacing snarl from the hills behind them. "There they are!" A voice shouted. "The enemies of the master!! They must die at all costs!!" With that Mephisto's thrall began pouring out from behind the foothills--and kept pouring out. By the hundreds.

As soon as the massive army began to emerge from the foothills it began its charge towards the Guardians. After fleeing for about 500 yards, the heroes came to the chain of craggy hills that encircled the valley. The huge boulders and loose rocks scattered all across the hills were very loosely packed, making their scramble up them very treacherous and difficult. Once atop the hill, Adam Warlock hit upon the idea of starting a rockslide to decimate and halt the trailing army.

On the other side of the hill were more rocky plains, and another 500 yards past the hills lay a river of boiling acid. Using their assorted and great powers, the Guardians traversed the river and eluded the hellish army of demons.

-

Just after it became obvious The Guardians had evaded the demon army, the sky became even darker and the lightning storm intensified. Following a loud howl, seeming to come from Mephisto himself, a torrential downpour of acidic rain began. After traveling through the acid rain for 3 hours they came across a weathered and wind-beaten silver castle.

Wishing to temporarily escape the rain they easily opened the gate and stepped inside. Inside the castle, they found themselves in a brightly lit chamber with tropical plants and lush tapestries. Before them was a full stocked banquet table with chairs, the entire room seeming out of place in Mephisto's holdings. 

Suddenly, a thin balding man emerged from an adjacent room, "Ah, how do you do, my friends? I am called 'The Keeper'. Is there anything I can bring you? Perhaps you would like something to eat? The rain will stop in another hour or so, so you may as well rest while you wait. Make yourselves comfortable for now."

Under Doctor Strange's guidance, none of the Guardians present accepted anything offered from the Keeper, as they should be suspicious of anything offered in the enemy's domain. Eventually, he began to offer exotic alien weaponry, and omnipotent super-devices, continuing to attempt to persuade them to fall under the Castle's curse.

True to the Keeper's word, the acidic rain stopped in an hour from when the Guardians had entered the castle. Refreshed, the Guardians toward where they believed Galactus to be very near.