Star Wars: The Clone Wars - Season 4 Episode 6 -

"Nomad Droids" On their return voyage to Coruscant, their Republic-cruiser is attacked by General Grievous. R2-D2 and C-3PO find themselves in a Y-wing and on a series of 4 mini-adventures, whilst trying to get back to the safety of Coruscant. The last of which is being trapped on General Grievous ship with captured Jedi Master Adi Gallia, until Jedi Master Plo Koon and his clone legion the Wolfpack rescues them.