The Future Diary (2011)

S1E3 Initial Failure

After narrowly escaping the deadly trap set by the 9th at school, Yuki and Yuno form a partnership with Detective Keigo Kurusu, the 4th diary holder. He suggests they spend a day at an amusement park, hoping to draw out the elusive 9th. As the day unfolds, Yuki stumbles upon a disturbing truth about Yuno, and it becomes clear that the 9th may have walked into a trap orchestrated by someone other than the 4th.