Special 10. probably took place in the mid 1950s after the Korean War. That's when Korea was divided into North and South. The girls mentioned about "war" and North Korean defectors.
As for Sungyeon, it's not confirmed yet. But I believe he was reincarnated into the same family over and over again. Let's see if he ever met Hosik in the next chapter. If not, then perhaps he went through several lifetimes without meeting Hosik And they were only reunited during the present timeline, which then explained Sungyeon's possessive behaviour.
Special 10. probably took place in the mid 1950s after the Korean War. That's when Korea was divided into North and South. The girls mentioned about "war" and North Korean defectors.
As for Sungyeon, it's not confirmed yet. But I believe he was reincarnated into the same family over and over again. Let's see if he ever met Hosik in the next chapter. If not, then perhaps he went through several lifetimes without meeting Hosik And they were only reunited during the present timeline, which then explained Sungyeon's possessive behaviour.