Mamma Mia! Here We Go Again aims to do what it says on the can. That is, be Mamma Mia, going again. But while many of the elements are the same as in the original —beautiful Greek island scenery; the actors frolicking among local folk and falling off boats; the knowing cheesiness; Pierce Brosnan singing his little heart out (alas) —you will be asking: where the hell is Meryl Streep? She’s on the poster but there’s no sign and no sign and no sign until, finally, at about 100 minutes in, she makes an appearance, and is wonderful.