All goes to plan until ~

The tale of a murderer (Allen) who uses the cover of Halloween night to causally transport his latest victim from the scene of the crime to his final resting place. Wrapping the body in tarpaulin and dragging it through the busy streets of London as a bloody Halloween prop, all goes to plan until an old school mate (Brassington) recognises the murderer and drags him along to a swanky Halloween party nearby, where a chance meeting with a beautiful girl (Tointon) takes his evening on an even bigger turn for the bizarre!

I'd like to know whether "according" is omitted before "to plan."
Thank you in advance for your help.