The phrase "plenty of surprises" means that there are many unexpected or unforeseen events, experiences or developments that are likely to occur. Full definition
About 70 per cent of the entries were familiar names to me, but there were plenty of surprises in there too. (393communications.com)
The plot is great (though a bit cheesy at times) with plenty of surprises along the way. (metacritic.com)
Not really, since there's still plenty of surprises along the way that make for a more enjoyable mystery, and that's all that really matters. (bullz-eye.com)