Han Ji-Han was a normal high school student who developed a special ability that allowed him to treat the world around him as a game called 'The Gamer'.
On his way home, he accidentally slips into another combat area, having to fight his way through zombies which he later finds out were amassed souls that Hwan Seong-Gon was collecting.
The story goes on, with Han Ji-Han deciding to stay in the world of the abyss, putting him in many dangerous situations as he grows stronger to protect himself and those around him.
Shin Seon-Il (신선일; Sinseon-il) is Han Ji-Han's childhood friend and attends the same high school as him.
After being sucked into the Great Labyrinth Era (A Protected Space), she is aided by Han Ji-Han and learns of the Abyss.
[1] As Naver Corporation started making web content globally available in 2014, many webtoons, including The Gamer, got official English-language translations.