Melody of the Underground Passage

When Kabapu sends Watanabe and his colleagues to investigate the sewers surrounding the Across base, Ilpalazzo dispatches Excel and Hyatt to deal with the intruders. However, even as the duo familiarise themselves with the Across security system, they discover a far more sinister breed of intruders lurking in the sewers- an army of Puchuus led by the nefarious Puchuu Queen! Will Excel and the others be able to stand against this overwhelming cute force of evil?