"Lonely" is the concept of a character named Loli who is turning 25 years old. She is having a party in her room, but her loved ones have all forgotten her birthday, leaving her to celebrate it alone. She feels a sense of loneliness as people gradually disappear from her life, but she realizes that there is one person who will always love her, which is herself.
As time goes by, birthdays may slowly fade from memory, and people might start to forget about our birthday. But ultimately, we are the ones who always remember and celebrate our own birthday. We are the ones who stay with ourselves and take pride in our growth. "Please take care of yourself."