天光（郭晋安 饰）是重案组的CID，为人刚直不阿黑白分明。在追查一宗连环杀人案时，发现疑凶竟是二十年前从父亲手上逃脱的犯人。天光父亲大河（许绍雄 饰）是一名资质平庸的警察，且粗心大意不思上进，不仅让罪犯逃走，更是死在妓女床上，让天光母子蒙受巨大屈辱。以写作实况小说知名的作家高珊（陈慧珊 饰）此次亦追踪着天光手上的案件，二人对案件的不同理解造成摩擦，纷纷竞逐真相。 一日，天光发现父亲的旧电话神奇响起，对方声称自己是警察，只是所说所讲都停留在八十年代。细问起才发现那竟是二十年前的父亲大河！二人合作无间，跨越两个时空，共同追查真凶。
一宝（马浚伟 饰）和傲蓝（杨怡 饰）是相识多年的好友，两人相互支持相互鼓励经历了风风雨雨，友情真挚又深厚。可是，随着时间的推移，傲蓝对一宝的好感渐渐超越了友情，面对傲蓝的改变，一宝的迟钝令两人在缘分的海洋中擦肩而过。 星皓（谢天华 饰）出现在了傲蓝的身边，性格相似趣味相投的两人很快就走到了一起，不幸的是，正当傲蓝沉浸在幸福中之时，星皓的前女友卓旗（曹敏莉 饰）卷土重来，在她的压力之下，傲蓝选择了放弃。一宝重新回到了伤心欲绝的傲蓝身边，替她疗伤，就在两人越走越近之时，星皓的再度出现令一宝与傲蓝的感情陷入了未知的境地。
Big Mood is a vivacious and rebellious portrayal of female friendship when infiltrated by the complexities of a serious mental illness. The six-part series will explore the messy pitfalls and idiosyncrasies of navigating adulthood through wicked humour, daft anecdotes, and unsettling truths. Best friends Maggie and Eddie have lived in each other’s pockets for ten years, through thick, thin, and multiple challenging eyebrow trends. But with the rest of their lives looming, careers hanging in the balance, and Maggie’s bipolar disorder making an unwelcome return to form, Eddie begins to question whether this friendship is really in their best interests. It’s a pivotal point in both their lives, bringing to the surface those all-important questions – could sleeping with your former History teacher be the key to happiness? Is a basement Rat Hotel a functional alternative to pest control? How do you stop your new psychiatrist giving you worry dolls? With their twenties behind them, Maggie and Eddie’s relationship faces the future – can it survive?
