I think this is the only Plattdeutsch song that I found all by myself in a charming little song book, namely Uns plattdüütsch Singbook. The song is Platt version of the better known traditional "Es waren zwei Königskinder". It's a sad little piece of lovers being treacherously dealt with by the evils of this world and are only united in death.
I first heard the High German version "Es waren zwei Königskinder" sung by the The King's Singers on their LP "Die King's Singers singen deutsche Volkslieder" sometime in the late 1970's.
I got to sing it a few times as a member of the Idle Fellows.

1.	Et wassen twee Künnigskinner De hadden enanner so leef, De kunnen tosamen nich kamen Dat Water was veel to deep (x2)	4.	"O Fisker, leevste Fisker! Je könnt verdenen groot Lohn Settet jue Nettkes to Water, Fisket mi mi den Künnigssohn!." (x2)
2.	"Leev Herte, kannst du nich swemmen? Leev Hert, so swemme to mi! Ik will di Kertes upsteken Un de söllt löchten to di." (x2)	5.	He sette sien Nettkes to Water, De lootkes sünken to Grund, He fiskde un fiskde so lange, De Künnigssohn wurde sien Fund. (x2)
3.	"Dat hoorde ne falske Nunne Up ehre Slaapkammer, o weh Se de di Kertes utdömpen, Leev Heerte bleev in de See." (x2)	6.	Se nahm in ehre blanken Armen, Den Künnigssohn, o weh! Se sprüng met in de Wellen, "O Vader un Moder, ade!." (x2)