Possibly Accidentally Deleted MAC OS?

So, I have no idea what I did while partitioning and whatnot for Bootcamp, but I appear to have accidentally deleted the MAC OS portion altogether. Pressing the option key on startup shows that there's literally nothing but the Windows 10 option there. On the other hand, I tried reinstalling with the Internet Recovery mode, but was unable to as the disk was locked.

Future prospects are not looking too good here, so I'd like some help.