Where did Jess go in season 5?

As it turns out, the reason Jess was absent from six episodes of “New Girl” Season 5 was that Zooey Deschanel was away on maternity leave, having given birth to her daughter in July 2015.

What episode does Jess come back in season 5?

Jess returns from jury duty and attempts to uncover the real identity of a juror sequestered with her.

Why does Jess go on jury duty in season 5?

If you mean why did Jess (the character) have to stay away then it’s a little complicated: Jess had been asked/ordered to participate in jury duty, she’s a firm believer in supporting the US justice system so goes intending to serve (however also believing it would be a 1 day trial).