Yuri and Kei are given accommodations at an all-girls boarding school from the 20th century. Yuri finds the life as an exchange student a lot of fun. Kei could care less, until she learns about some ghost stories about the school and experiences some of the horror.

The rain catches Yuri and Touma in the city and they end up at a flower shop where Touma falls in love with a girl who works there. Kei and Yuri pick up on the computer geek's change in mood, and readily give him love advice on the scary thought of asking the girl out.

Kei is on a plane trip but some enemy fighter plane is after them and it shoots the plane down into the snow covered mountains. Kei manages to save a baby as she bails out in time before the big crash and explosion, but not only does she have to deal with calming down a baby, but also the bad guys who pursue them with intent to kill.

A teenage girl named Monica has been training all her life to carry on her family's deadly assassin heritage. Her first assignment is to go after the Dirty Pair. Kei and Yuri go to a vacation resort to relax but soon find themselves on the guard as bombs, traps, and deadly attacks appear wherever they go.

A felon sprung out of prison transport makes a deal with a crime boss to command and pilot an advanced assault mech, but first he wants to borrow the mech to go after Chief Poporo of the 3WA. Soon afterwards, bombs start going off all over the city and the Chief's life is in danger as the mech raids 3WA Headquarters. Kei and Yuri try to protect him, but what complicates things even more is that the Chief's daughter is at the office for a visit.