A Callum Phillips try and two first half penalties gave the North, who reached the final last season, a real chance of kicking off their season on a winning note.
However, having been locked together at 6-6 at half time, it was the Dragons who took control with tries from Hallam Amos, Jack Dixon and Dominic Franchi.
Ethan Davies added to his two first half kicks with a second half conversion of Dixon's try whilst Niall Martin improved Franchi's score late on..
There was also a winn ing start for the Ospreys U16s who bagged a bonus point in defeating Blues South 31-7 at Llandarcy.
Matthew Jenkins and Evan Yadley crossed for tries in the first half with Ben Roberts and Sean Macdonell-Roberts adding further tries after the interval.
Outside half Sam Davies kicked four conversions and a penalty to complete the rout with Jordan Phillips crossing for the South and Gareth Thompson adding a conversion.
The Scarlets U18s failed to carry on from last week's consummate victory over Gogledd Cymru - going down 18-6 to the Blues at Parc y Scarlets.
James Russell kept the Scarlets in touch with a couple of penalties, but the Blues made sure of victory thanks to tries from outside half Joseph Griffin and blindside Callum Thomas.
Griffin, who was outstanding throughout, added a conversion and two penalties to secure an important away success. The evening finished on a sour note for the Scarlets with Kirby Myhill and Iolo Evans both leaving the field injured.