The bookstore is also an amazing resource for English teachers in Seoul. I never knew small stores specific to children's English books even existed in Seoul before working here. They have English games, books, coordinating workbooks, puzzles, and English cartoons. I've used some of the storybook/workbook combos for private lessons which has been way great way to supplement my lessons.
On the right there is an entry way to the elevators. The bookstore is on the 5th floor.