Hi, Norton!
We've got a couple questions and troubleshooting steps for you:
1. Did you start a new file after downloading the mod and play through the prologue? Mika shows up there, so it's a pretty easy way to confirm the mod is working as intended.
2. Is script_hg.rpy among the scripts within the "game" folder? If not, you will need to redownload the mod.
If these don't work, we have a tech support channel in our Discord and can provide you with more in-depth help there.
Thanks for reaching out!