On May 24, South Korea's President Moon Jae In returned to Seoul from Washington, thinking his fourth meeting with US President Donald Trump since taking power last year had gone well.
A planned summit between Mr Trump and North Korean leader Kim Jong Un looked to be on track, and Mr Moon thought he had dispelled the United States' doubts over Mr Kim's sincerity towards the meeting, and his willingness to denuclearise North Korea.
But on the very same day, Mr Trump pulled the rug from under Mr Moon's feet. He made a shock announcement that the summit was off, forcing Mr Moon, 65, to convene an urgent midnight meeting with key ministers and aides.
Mr Trump's decision was a blow to Mr Moon, whose parents are North Korean refugees who fled to the South during the 1950-1953 Korean War. The South Korean leader has staked his credibility - and possibly the presidency - on realising permanent peace on the Korean peninsula.
Any peace treaty or agreement that to formally end the Korean War will have to involve North Korea, China and the US, signatories of the armistice. There are fears the US may now ratchet up pressure on North Korea by tightening sanctions enforcement and re-energising military planning.
But the former human rights lawyer, hailed by CNN as a "masterful dealmaker", is not deterred. He turned the tables on naysayers with the brilliant move of holding a surprise summit with Mr Kim, their second in a month, on May 26. Their second meeting was held on North Korea's side of the truce village of Panmunjom, located on heavily fortified Demilitarised Zone (DMZ).
Both leaders agreed that the US-North Korea summit slated for June 12 in Singapore "must be successfully held". In a televised address on May 27, Mr Moon said Mr Kim agreed with him on the need to have direct communication with Washington to remove misunderstanding between them, and to have sufficient dialogue ahead of the June 12 summit.
Efforts to revive the cancelled summit preparations gathered pace after the second inter-Korea summit.
Mr Kim sent his right-hand man and former spy chief Kim Yong Chol to the US to meet US Secretary of State Mike Pompeo and Mr Trump. The four-star general is the most senior North Korean official to visit the White House since Vice-Marshal Jo Yong Rok met President Bill Clinton and US Secretary of State Madeleine Albright in 2000.
Mr Trump announced after receiving Mr Kim Yong Chol on June 1 (June 2, Singapore time) that the June 12 summit is back on.
On April 27, Mr Kim had promised Mr Moon at their historic summit on the South's side of Panmunjom that he would not interrupt Mr Moon's morning sleep with missiles launches any more. Mr Moon is adamant it stays that way.
With input from South Korea Correspondent Chang May Choon