The story feels like its even written by Ishida, so honestly hope its not canon.
For those who want to know but dont know japanese, short summary.
- Hisoka gets taken in by circus.
- Morino is the man who took him in
but the other members dont like it
- Hisoka watches the performance
and Morino uses Nen for his tricks
and that interests Hisoka
- one of the members gets hurt and Hisoka is
ultra talented and even able to replace
- Hisoka wants to learn Nen, Morino initially
- but Hisoka has also talent in learning it
and gets taught finally
- Some gal who also had been taken in by the
circus troup get attacked by some killer.but
Hisoka is able to fend him off.
- Hisoka confronts Morino about being the killer,
kills Morino and goes away.