In terms of narrative expediency and proximity to the anticipated test, by joining the Royal Naval Division, Brooke initially got exactly what he wanted: immediate active service. He was scarcely trained when he was sent to Antwerp on 4 October as part of an expedition that later garnered for Winston Churchill, its architect and commander, a great deal of criticism. For Brooke, his early knowledge of the deployment represented the first in a line of ‘dead secrets’ shared with his friends Jacques Raverat, Cathleen Nesbitt, Katherine Cox, and his mother in the months leading up to the Division's departure for Gallipoli. This bit of knowledge was gleaned from a lunch at the Admiralty on 23 September.

His relatively informed position again marked him out as not necessarily a singular, but a privileged case. Brooke's ‘secrets’ were in essence rumours, although better informed than most, helping him to make sense of his war. One insight that emerges from the study of letters, war diaries, and memoirs from the First World War, and probably any war, is that these writings impose a narrative structure on to situations that are, in actual experience, bewildering. Brooke's reading and writing about the war also served to raise his expectations of what was to come, and to heighten his sense of proximity to the war without physically drawing him nearer to it. In early October, he was impatient to cross the line, to experience a rite of passage wherein ‘the initiate ultimately leaves the liminal state and is reintroduced to the community with an altered and superior status’.

The overall aim of the Antwerp expedition centred on plans devised as early as 1905, with a purpose that was threefold: establish a base through which the navy could easily supply the army from Britain; attack a portion of the German flank that was vulnerable to harassment by a small force; and maintain autonomy from a rival command, something less likely if operating from a French, as opposed to a Belgian, port. Both General Joffre in France and Lord Kitchener refused to send troops, while Churchill was keen on engaging directly in the fight. Brooke's Anson Battalion travelled across the Channel, landed, marched, and took up a position near the village of Vienne Dieu. The weather was warm and dry.