‘Journey to the Centre of the TARDIS’ is season 7, part 2 of New Who.
The Doctor is teaching Clara to drive the TARDIS so he turns off the shields, as you do.
(I’m not sure how long the TARDIS has had shields; I’m sure they’re a relatively recent addition, just like the sonic screwdriver’s scanning abilities.)
As soon as the shields are switched off in the infinite regions of time and space, a rogue ‘salvage’ vessel cripples the TARDIS while hauling her on board.
Miraculously the Doctor ends up outside the wreckage under a pile of junk, while Clara is trapped somewhere in the depths of the now-infinite TARDIS. The wreckers can’t open the TARDIS door even with their power tools. The TARDIS has ruptured fuel lines, leaking toxic gas from which Clara must be rescued.
Spoilers, Sweetie (to avoid spoilers go to the Conclusion)
The Doctor tempts the salvage crew by offering rewards beyond imagining if they help him find Clara before it’s too late. The crew accept his offer then steal TARDIS components; the TARDIS isn’t happy so she turns her corridors into a maze.
The absolute highlights of this episode are seeing the TARDIS ‘engine’ (a star) and the library where books come in many forms.
The lowlights of this episode are the glowing-eyed zombies, a nonsensical time paradox and another instance of ‘We can’t do X because we’ll die’ promptly followed by – you guessed it – everyone doing X but only the redshirts die. Doctor Who and reading in my childhood gave me a love of time travel stories and paradoxes but there are mandatory rules for paradoxes to avoid misquotes of the Hunchback of Notre Dame: ‘The Plot! The Plot’!
This episode is a must-see to follow the seasonal story arc that will culminate in the 50th Anniversary Episode. However, love of characters and exploration of the TARDIS are essential to substitute for the lack of logical plot. The story is fun, exciting and a great way to introduce the kiddies to the Way of Science Fiction.