描写拥有完全不同金钱观的男女同居生活的爱情喜剧。
在玩具公司财务部工作的 OL 女主角,因为生长背景及教育环境,让她成为节俭的人。追求着座右铭为「一生清贫」,事物一定都要物尽其用,绝对不浪费及消费这样的生活方式,而男主角则是玩具公司的富二代,生活极度奢华浪费,因为过度挥霍而激怒父亲,并被转调至财务部,价值观完全相反的两人,在巧合之中莫名开始了同居生活,也渐渐燃起爱情火花。
Big Baby tells the story of Adam Lewis, a successful horror screenwriter struggling for inspiration for his latest script. After a graphic and realistic nightmare of a hulking man dressed in a baby mask and onesie who axe murders his girlfriend Kate in the middle of the night, Adam gets the inspiration he needs for his new screenplay. Excited about the direction his story is taking, he starts losing himself in his script. Things are better than ever for Adam and Kate until “Big Baby” starts appearing in real life and tormenting and killing victims fueled by his own revenge. Characters from Adam’s script begin to pay him visits pleading for their lives, and he quickly realizes he holds their fate in his hands. Power and fear completely consume Adam until his girlfriend Kate is terrified of the man she once loved.