The history book on the shelf is always repeating itself

What is going on

The four friends laid in their hospital beds facing each other eating their lunch. Björn was the only one of the four that was unscratched. Frida laughed, "Who would have thought that the week of the 50th anniversary of us winning Eurovision would begin like that!". "Just you wait, with our luck things are bound to only get crazier from now on. For all we know flying elephants and swimming giraffes aren't out of question! Can't we have a normal, calm, possibly a little boring day?" added Agentha. "No!" exclaimed the other three and all four burst into laughter. "Maybe laughing wasn't such a good idea!" exclaimed a pale Agnetha before she and Frida rushed into the attached bathroom closely followed by the boys. Björn and Benny held their hair while they emptied their stomachs. When they were done, they all sat on the bathroom floor, Frida and Agentha sitting on their loving men. Slowly they made their way back into the main room careful not to agitate their stomachs again. They laid back in their beds Björn holding Agnetha close, mirroring the same image of Benny and Frida. The afternoon was spent napping and chatting before doctor Persson who was now in charge of the care all of them. She requested for them to stay in the hospital for a couple more days. All members agreed especially since neither Frida nor Agnetha were feeling up to anything.

A couple days have passed by and nothing much has changed. In fact, both girls seemed to be worse and worse every day. It was now Thursday evening and just past 10.00 PM just 2 hours left until Agnetha's 74th birthday. The couples laid snuggling into one another enjoying each other's company. "Honestly, now this must be the craziest thing yet. What could be happening to us Frida? It almost feels like..." there was a moment of silence Frida and Agnetha locking their gazes and the boys just sitting there confused, not knowing what the girls were silently talking about. "I mean it can't be, it's been years since even the possibility has been out of the window," said Agnetha. Bothe of them were exhausted, constant throwing up, lack of sleep combined with the cold that has suddenly taken over Sweden really took a toll on them.

The silence grew as all four desperately tried to get some sleep, it was obvious they all needed it. It was no minutes till midnight when suddenly they were all rudely awakened by a sudden bang. Holding each other's hands all four jumped from their beds staying close together not daring to split. All the windows opened in an instant, snow and wind now fully entering the room. Lights began to flicker before all went dark.

It took a couple of minutes before the lights were back on and nurses came in the room rushing to close the windows. But by that time no trace of ABBA ever being in that hospital could be found. The wind and the snow destroyed all the evidence. The nurses looked around the room and into the bathroom. Where were they? Where did ABBA go?