聽說霓虹燈牌裡住了燈神，當許願時燈牌亮起即象徵願望會成真。

江美香（張艾嘉飾）難以接受丈夫楊燦鑣（任達華飾）驟然離世，一直記著與亡夫在霓虹招牌燈下的浪漫往事。在整理家中的遺物期間，她發現了開啟亡夫秘密工場的鎖匙，在那裡遇到他的冒失徒弟Leo（周漢寧飾）。原來楊燦鑣一直希望重造一個已拆除的霓虹燈牌。美香為完成他的遺願，一步步了解每個霓虹燈牌的故事，踏遍街巷，親手燒製霓虹光管。亡夫的秘密遺願逐漸揭開，女兒楊彩虹（蔡思韵飾）卻正計劃離港......

​

香港曾以滿街霓虹燈而聞名世界，隨著時代變遷、清拆工程，昔日的燦爛繁華似乎已成往事。劇組在拍攝期間需與時間競賽，留住都市光輝。不同的意境符號貫穿全片，暗喻著這座城市之餘，也對照著力挽狂瀾的香港人。

​

Middle-aged widow Mei Heung (starring Sylvia CHANG) has gone through countless sleepless nights since the death of her husband, Bill (starring Simon YAM). One day, she finds a key among the items that Bill left behind, leading her to his secret neon workshop and meet the young apprentice, Leo (starring Henick CHOU).  She learns from Leo that Bill had an unfulfilled last wish: to recreate a demolished legendary neon sign.  With Leo’s help, Mei-heung tries to uncover the story behind the sign and learns the craft of blowing neon lights in hopes of fulfilling her deceased husband's last wish with her own hands.  Along the way, Mei-heung reminisces about her beautiful encounters with Bill and unearths pieces of Bill's past as if they are the last consolation left by him.  Meanwhile, Mei-heung’s daughter, Prism (starring Cecilia CHOI), plans to leave Hong Kong with her fiancé, but she is unable to break the news to Mei-heung.

 

As clues of the legendary neon sign gradually emerge, the secrets that Mei-heung couldn't face are about to be revealed...