invasion invasion episode british science fiction television series originally broadcast january series commissioned script episode written pilot bank holiday special serves introductory functions pilot episode focuses thirteen year old girl discovering existence aliens discovering creators soft drink called bubble shock harbour destructive secret teams investigative journalist prevent plans plot thirteen year old girl recently divorced father house opposite journalist time traveller night moved maria ethereal light house discovers horrified fascination star poet morning neighbour visits maria inviting town free bubble shock bus travel tour factory arrive factory led security collects dna transfer supervision factory owner having girls making plans follows factory interviews able approval drink fast ingredient unique drink resisting analysis told bubble shock satisfying needs western world way killed secretary tour attempts phone maria unknown beast mother annoyance staff orders switched killed maria attempts phone sets causing escape transferring focus maria escaping encounters escape women bathroom enters surprised manage escape factory albeit arrive road sarah warns maria involved life dangerous factory guards causes treatment received revealing true form having discovered live street uses representative escort home maria realises sight discovered sarah tries run house eventually realising intent brings inside giving chase able repel discovery attic tells teenagers aliens years ago met doctor man like took time space adventures suddenly ended met chance school reunion long ago realised fond brief reunion safe sealing black hole analysed ingredient computer shouting contacts requests leaves earth refuses retaliation takes control majority human race races factory enter drives bus wall reveals mother explains human dna designed investigated bubble shock improved uses alien given realising signal strong kill mother maria escape factory explodes following evening agrees adopt agrees maria luke wanted child episode closes monologue space strange adventures earth knows look continuity reappears series serial enemy trying find luke mentions harry referring deciding luke outside reference plot similar factory alien fluid soft drink control humans world production doctor previously played offered role ease transition fourth declined agreed star pilot episode spin series company brought popular character appearance doctors temporarily stopped acting order raise family lent voice big finish audio productions returned doctor titled tenth doctor episode school reunion appeared series finale stolen earth journey end second final swan song tenth doctor end time concept writing envisioned previous companion explore role eventual fate doctor companions convinced appear second series episode school reunion proposed spin davies teenage doctor denied favour spin revolving surprised agreed sign project rights appear series secured explain non appearance production team gave cameo fixing black hole inadvertently created switzerland episode written davies roberts drew outside sources parts plot example allusion star book revelation roberts called novel highest science inspiration bubble shock broadcast reception scene invasion shown december interview released day later interactive advent calendar doctor clip lasting minute length interview episode airing gathered million viewers audience share film aired invasion higher overall reach invasion slightly higher number viewers head head episode audience appreciation index average score episode drama programme adapted novel written book published paperback november
Invasion of the Bane