貝多芬（岑建勛 飾）和阿秋（吳耀漢 飾）是一對好朋友，也是搞笑鬼馬的便衣搭檔。他們常將警局鬧得不可開交，連上司陳辦（陳欣建 飾）也頭疼不已。不過，自從阿秋和安娜（葉德嫻 飾）結婚之后，貝多芬就變得孤苦伶仃，可憐兮兮。最終貝多芬搬到了阿秋家，和這對小夫妻湊成一個笑料百出的三人世界。　　陳辦不堪其擾，將二人調到素有“鯊魚田”之稱的田警司（田俊 飾）麾下，兩人被好好整了一番，苦不堪言。另一方面，陳辦在執行任務時被多年前的宿敵飛天蠄蟧（林正英 飾）陷害。貝多芬和阿秋深知老上司被冤枉，于是明察暗訪，發誓揪出幕后真兇……

國際知名微縮畫家Alif遭遇嚴重車禍后失憶，一名老婦人突然現身，自稱是他失散18年的母親。Alif在拼湊破碎記憶的過程中，逐漸發現母親的身份疑點重重，同時揭開了自己童年、家族與馬林?昆當傳說背后的黑暗真相。他必須在身份崩塌與創傷反噬中，直面自己的過去，終結這場由傳說編織的懸疑迷局。

　　Kyohei Aizawa, an assassin for a covert non-governmental espionage group in Japan called "SEEK", is grieving over the loss of his girlfriend from a tragic plane accident. The leader of "SEEK",Ryo Mikumo, contacts him for an emergency mission; save a fellow agent, recover a new highly explosive liquid called "RDX@", stop a ruthless Yakuza leader, Sojiro Kotsuki, and his gang before they take over Japan. Although the Ninjas were thought to have disappeared... the new breed of assassins live on helping to protect Japan and all that is right; the Ninjas are coming soon.