ソラちゃんとましろちゃんが確定申告に挑戦。
確定申告終わってないのに現実逃避するために書きました。

Sora-chan and Mashiro-chan attempt to do a tax return.
I wrote this to escape reality, since I haven't filed my own tax returns.

The word for "tax return" can also mean "final declaration".