You can take this plot three different ways.

One you are either an assassin who is trying to protect Stray kids.

Two you are an assassin trying to kill them.

Three this is an entire different universe and you are all assassins in training together.

Stray kids are eight members. Chan, Minho, Changbin, Hyunjin, Jisung, Felix, Seungmin, Jeongin. Have fun.