After Jacob and Charlotte's masterful invasion of the ice city, they started to slowly move toward the ice tower, just as Jacob planned.
But half a day later, a commotion broke into the ice city among the monsters when one of them discovered the unidentified hole in the ice wall.
Almost instantly, the monsters reacted by sending ten grounds led by large monsters at the peaks of epic-tier-9, and all of them controlled at least five hundred small snow monsters.
All of them selected different entrances and started to comb through the maze for intruders. At the same time, more units were made to comb through the city.
This naturally put massive pressure on the two infiltrators. But they had their way to make sure they wouldn't get noticed, and since many snow monsters were running around the city or combing the passages, no one noticed the missing monsters from the house.