The TARDIS had seven keys , 5 of them hidden throughout the ship . Donna always had her key on her keychain , the souviner one from Pompeii , when they went back after the eruption of Vesuvius . And she knew the Doctor always had one on him , somewhere deep in the pockets of his suit , or in his trench coat.
Donna knew that , as one Sunday afternoon, she was bored , and she asked the Doctor to tell her where they were .
' They're hidden ', he told her. ' I have placed them in spots that you won't be able to locate them', he added, like a challenge .
So Donna set off on her mission to find the keys
She found the first one hidden underneath the blue teapot in the kitchen , sitting solo on the shelf .
She found the second one hidden in a copy of Gullivers Travels , that was sitting on a table in the library.
The third one was located , deep in the pockets of a leather jacket in the wardrobe .
The fourth key was found , not sure how , or why, in the Doctors own bathroom , rattling away in an empty hair gel container.
The fifth one was a bit harder to find . She spent nearly three hours searching for it , the Doctor trailing her every move throughout the TARDIS, smirking but not saying a word .
' WHERE IS IT ? she demanded.
'Not telling ' he replied gleefuly . He was enjoying this .
Donna searched for that key , well into the night , until she finally gave up. The Doctor had found the perfect hiding place , and it had stumped her .
'I give up' she sighed , as she sunk into the pillows of the sofa .
The Doctor looked up from the book he was reading and surveyed her .
' Its not like you to give up, Donna' he told her . ' Keep looking '
' You have a really great hiding place ' she replied , half praising and in half defeat .
' You'll find it eventually' he encouraged her .
Donna found that fifth key two days later , when she was going through her bag . It was found in one of the compartments , completely forgotten . She ran into the console room , where the Doctor was doing some repairs
'Found it !' she exclaimed, proud of herself .
The Doctor looked up from underneath the console, and grinned at her .
' You really should stop losing keys Donna, I really can't keep making copies for you '