Kung (Eric Tsang) and Kin’s (Jacky Cheung) rivalry goes way back to the seventies when they fought over the same girl, who eventually became Kung’s wife (Anita Yuen). Now they run competing phone stores right across from each other on Mongkok’s busiest street, and stretch their minds trying to outdo each other with crazy promotions. There’s absolutely no mixing with the enemy in these parts – until Kung and Kin’s kids fall for each other! Further chaos breaks out when the landlord triples the rent of all the shop owners to force them out for redevelopment.

Phil and Claire Foster fear that their mild-mannered relationship may be falling into a stale rut. During their weekly date night, their dinner reservation leads to their being mistaken for a couple of thieves—and now a number of unsavoury characters want Phil and Claire killed.