De Plus was part of the day's breakaway that was still clear on the fall from the Sormano, a descent his teammate Dan Martin once described as "one of the most dangerous downhills of any WorldTour racing".
The 22-year-old was chasing Mikel Cherel (AG2R La Mondiale) on the descent when he misjudged a bend and hit the guard rail and was launched into the air and over the edge.
The heart-stopping drop was fortunately not as far down as it appeared from the cameras.
