Malang, East Java. In 2017, There was a coffee shop named Poststukken which opened the consultation about philately. Back then; Lucky, the owner of the coffee shop with his male calico bobtail cat, Kelana, meet an albino man named Sebastian who was the son of serial killer victim at Oslo Harbor. They took their first case to help Sebastian returning his white swan’s necklace and find the missing letter that was considered as his mother’s last letter. During their investigation, with Kelana’s sensing ability; they got involved into unexpected cases about philately and solved together. Until in 2018, at the incident in Malang Youth Philatelic Festival, both of Lucky and Sebastian found an unrevealed relationship between their families.