This is an unexpected turn of events.

情势的转变出乎意料。

youdao

An unexpected turn of events brought their idyll to an end.

一件始料不及的事情终结了他们的爱情。

youdao

My second brother was at a loss for words at such an unexpected turn of events.

NPR: Literature and Lullabies from the 'Axis of Evil'

We wouldn't quite call it an unexpected turn of events, but it certainly qualifies as dramatic -- Motorola has pulled almost every Android device in its roster from its German site, leaving only the RAZR HD and RAZR i behind.

ENGADGET: Moto pulls phones and tablets from German site pending software update