During this time, Grace became even more aware of the deplorable living conditions forced upon many citizens of Dublin. In the early 1900s, Dublin slums were considered the worst in Europe. Grace and her sisters began working with several groups founded to help improve the lives of the Irish poor, including the Daughters of Erin founded by Maud Gonne. The Gifford sisters also assisted with supplying school meals for inner-city children, a project instigated by James Connolly, then a Labour leader, and strongly supported by Maud Gonne.

The sisters also became strong supporters of the Irish Women's Franchise League, a militant organization working to obtain voting rights for women. In 1911, Grace was part of a group of women protesting outside City Hall against a planned "Loyal Address" from Dublin Corporation to King George V and Queen Mary.

Mrs. Dryhurst, the journalist who introduced Grace and her sisters to many of the burgeoning Irish political and social movements and its leaders, also introduced Grace to her future husband. The introduction took place in the winter of 1914-15 on the steps of St. Enda's School, established by scholars Padraic Pearse and Thomas MacDonagh to educate young Irish men of the importance of their own culture along with more traditional studies. Joe Plunkett, fluent in several languages, took Irish language lessons from Thomas and maintained close friendships with Thomas and Padraic.

Joe Plunkett

Grace was deeply interested in Catholicism and often attended the Pro-Cathedral, located in a poor area of Dublin. She was impressed with the faith and devotion shown by the parishioners, in spite of the poverty most of them endured. While growing up as a Protestant, Grace had attended the prosperous Church of the Holy Trinity in Rathmines. Her opinion of its congregation was that they were more intent on showing off their fine clothes and making social connections than seeking spiritual guidance.

Joe's devout Catholicism and Grace's strong desire to learn more about the Catholic faith formed the basis for their friendship, which developed into love. Joe also came from a prominent Dublin family, whose lineage included the Earls of Fingall and Dunsany in County Meath. There were both Protestant and Catholic branches of the Plunkett family. Another ancestor was Archbishop Oliver Plunkett, who was martyred in London in 1681 after being falsely accused of involvement in the Titus Oates conspiracy. He was venerated as a Roman Catholic saint in 1975.

Joe's father, George Plunkett, was a Papal Count and a barrister. Count Plunkett was also Director of the National Museum of Science and Art. He had strongly supported Charles Parnell and, for a time, had hoped for a political career. Count Plunkett wrote for nationalist and cultural newspapers, collected Irish music and lectured to various cultural organisations. He served as secretary of the Society for the Preservation of the Irish Language, which later became the Gaelic League. The family was actively involved in Nationalist and Union movements. In 1915, Count Plunkett joined the Irish Republican Brotherhood, taking his oath from Joe.

Joe received his secondary education at Catholic schools in both Dublin and Paris, developing a special interest in Catholic philosphy and the mystical writings of the Church. While attending the English Jesuit School in Lancashire, Joe received military training from the Officers' Training Corps.

At the time he met Grace, Joe was actively involved in the planning of an armed insurrection against British rule of Ireland while serving on the executive of the Irish Volunteers. The Volunteers, originally formed to defend Ireland's neutrality against a possible war in Europe, became one of the primary forces behind the Irish fight for freedom. Since England was occupied with World War I, an armed battle was planned in Dublin that the leaders hoped would lead to the Home Rule Act finally being passed.

Many members of the Irish Republican Brotherhood joined the Volunteers and began planning the final stages of the Rising and drafting the Proclamation of the Irish Republic, which would be read by Padraic Pearse at the onset of the Rising. Joe became director of military operations for the Irish Republican Brotherhood, with Padraic and Thomas taking other leadership positions.

Joe was also a published poet and writer, gifted musician and head of the literary magazine, The Irish Review. He and Thomas co-founded the "Theatre of Ireland" which produced new plays by Irish playwrights, including two written by Thomas. Due to having tubercular glands in his neck as a child, he suffered from advanced tuberculosis. It's believed that Grace did not know the extent of Joe's illness.

Grace and Joe became engaged in December 1915, although they did not publicly announce their plans for an Easter wedding until February 1916.. The most likely reason for their secrecy was Isabella Gifford's opposition to their relationship, which was based on eitherJoe's health problems, his religion, his political activities or all three. Grace was received into the Catholic Church on April 7, 1916, at the University Church on St. Stephen's Green.