Complex sentence: Gabrielle O'Brien and Michael Hendry are sent to infiltrate the infamous' Slasher Boys', led by' Major Dee'; and Gabrielle is injured and sent back to campus.
Split into simpler sentences: Gabrielle O'Brien and Michael Hendry are sent to infiltrate the infamous' Slasher Boys', led by a man who calls himself Major Dee. Later on Gabrielle is injured and sent back to campus.