Chapter 19:
Koto takes her mother from the Shrine's Holy Grounds to the Looking Glass City.
Chapter 20:
The three siblings enjoy their time with their mother, but...
Chapter 21:
Koto tries to find out the secret of her birth from her mother, but instead she's asked to save her poor father.  With no place for her feelings to go, she takes them out on Myoue.
to protect the Looking Glass 
City, just like you promised!
um die Stadt der Spiegel zu beschützen, wie ihr es versprochen habt.
protegiendo la ciudad al otro lado 
del espejo, como prometieron!
Habéis protegido la ciudad 
del otro lado del espejo.
para proteger a Cidade Através
do Espelho, como prometeram!