S1·E24 The Maiden's Voyage

Faust and Ieyasu explain to Otaru that the only way to stop the Mesopotamia is for the three maiden circuits to act as a replacement for Lorelei. However, the only way of reaching it is by combining the Japonessgar and Gartland's Sabbelburg 2. Not wanting to lose the marionettes, Otaru instead opts to head there by himself to destroy the ship and save Lorelei.