SwordLord against Apocalypse

Fei world got absorbed by higher world rampaging mana changed everything. Animals mutated and are faster and stronger than everything humans have known to this day. More than 60 % of human population mutated and become zombies or something worse. Lucas Rain only heir of the Rain corporation creators of Lynx city is meeting mysterious man who claims that in 20 minutes world will be overrun by zombies. What MC will change in this 20 minutes? I'm not native speaker so please show me all mistakes I will made.