After losing the toss and being put into bat, Seekkuge Prasanna's whirlwind half-century ensured that Sri Lanka made 286-9 despite a tough start.
England were on the ropes in reply after losing early wickets, but Jos Buttler and Chris Woakes shone to rescue them, whilst Eoin Morgan and the aforementioned Plunkett both had parts to play in securing the draw.
Prassana stars for Sri Lanka
The hosts restricted Sri Lanka early on, with the tourists only at 59-3 after the first powerplay, captain Angelo Matthews powering through to eventually make 73, albeit a slow one from 109 balls.
It was Prassana's innings which allowed Matthews to play at a more measured pace, hitting a 24 ball fifty after coming in following a solid partnership between Dinesh Chandimal and the skipper.
Prassana struck the ball all around the ground, managing four sixes from five balls at one point, before eventually being caught and bowled by Woakes for 59 from 28.
Sri Lanka started slowly and finished slowly, with Prassana's knock in the middle the main reason for their positive score. Farveez Maharoof did contribute late on, finishing unbeaten on a run-a-ball 31.
England start poorly before Woakes and Buttler shine
It looked like an excellent score as England toiled at the start of their innings, reduced to first 7-2 and then 30-4 as Alex Hales, Jason Roy, Joe Root and Jonny Bairstow were all dismissed cheaply.
Eoin Morgan scored 43 as he and Buttler began to repair the innings, but the Ulsterman was followed by Moeen Ali in getting out before England had even reached 20 overs, leaving them in real trouble at 82-6.
It was at this point that Woakes and Buttler took the game back to Sri Lanka, securing a partnership of 100 from 109 deliveries, the Sri Lankan attack unable to cope with their aggressive style.
A thrilling finale
However, they visitors did eventually wrestle back the momentum when Buttler went seven runs short of his century, and David Willey quickly followed, leaving the home side in need of 50 runs in less than five overs, with two wickets remaining.
Up step Plunkett and Woakes, the latter of which would make the best ever ODI score for a number eight batsman, finishing not out on 95 from 92 balls.
When Woakes whipped the ball into the legside with two balls to spare, and England were needing 10 to win, premature celebrations from the fielding team arose, with them thinking that England would only make two runs, leaving them with an impossible eight to win off the final ball. However, the unlikely heroes scampered through for three, leaving Plunkett to face the final ball, needing six to tie the game.
He did that, as Nuwan Pradeep bowled him a slightly shorter ball than the deliveries that had been sent down to Woakes, Plunkett crashing the ball back over the top for a maxium.
Game tied with England at 286-8, and a thrilling start to the series.