Forum:Dark Caius VS Morphing Jar 2

Lets say I have a Morphing Jar #2 face down and a Book of Taiyou face down. My opponent tribute summons for Caius, and targets my morphing jar. If i activate Book of Taiyou on morphing jar, what happens? Does Caius' effect still resolve and morphing jar is removed from play instead of returned to the deck? Does morphing jar's effect resolve?