No Reserve

• Wayne Lai as Suzuki Kazuo (鈴木一雄) and Kong Sheung-hung (江尚紅), a pair of twin brothers who were separated at a young age. Lai, who was willing to push aside other filming offers in order to accommodate his schedule to film No Reserve, was the first of the cast to be confirmed in late 2011. In regards of him portraying two different characters, Lai said, "It is difficult. The older brother ends up in Japan and is educated with Japanese culture, later becoming a Japanese businessman. He is also a man with wild ambitions and has a harsh childhood leading him to become a mad man. The younger brother stays in China and joins the guerrilla team... in the end, the two brothers will have to confront each other."[3]
• Myolie Wu as Cheung Kei-sang (張寄生), a special agent for the Chinese Communist Party. She face the tragic loss of her father and younger brother leading to become a secret agent. Wu expressed that No Reserve is one of her most challenging scripts: "It is a powerful [story], with many ups and downs. It takes place during a war, so there will be tragic partings of life and death... it forces one to make certain decisions and choices. It's a brilliant script." On replacing Sheren Tang as the franchise's female lead, Wu admitted that the role had given her a lot of pressure, but said, "It is a completely new story. No one can replace [Tang]. Our performances will inevitably be compared, but I will do my best on my part."[4] As for Tang's response, she said, "[Producer Lee] has already stated before that he could not come up with a suitable story line for me and [Lai] in [No Reserve]. I trust his judgment."[5]
• Edwin Siu as Chau Sai-kai (周細雞), a Kuomintang special agent who eventually goes psychotic, raping and assaulting random innocent people for his amusement. He became the enemy of Kong Sheung-hung and Cheung Kei-sang. Siu said that he has never come upon a more challenging character to portray, also expressing, "But no matter how many girls I touch, I will still be faithfully in love with Sang (Wu's character) until the end."[3] Siu is the second cast member to be confirmed to star in No Reserve. In 2008, Siu was in final negotiations to star in Rosy Business, but ultimately withdrew due to a schedule clash.[6]
• Sire Ma as Kam Wan-ling (金韞凌), a fallen Qing dynasty princess. She has never been to the outside since when she was a child. Sneak away home to look for adventure in the outside world. She admired Kong Sheung-hung. She has a tattoo on her back connecting to the secret treasure of the former Qing dynasty. Ma was thrilled to be able to take part in the franchise, saying, "I have been hoping to take part in the franchise since I first heard that a third was in the making. It's a dream come true."[7]

• Li Shing-cheong as a former Qing dynasty official having false hope of restoring Qing dynasty raised Ling.
• Susan Tse as Ling's nanny who raised her with few Qing dynasty remnant.
• Lau Kong as a special agent of the Chinese Communist Party, supervisor of Kong Sheung-hung and Cheung Kei-sang.
• Cecilia Fong as the mother of Suzuki Kazuo and Kong Sheung-hung. She has one regret of having lost her older son during an earthquake in Japan.
• Yoyo Chen as ex-wife of Chau Sai-kai who he marries because of Kuomintang undercover mission to get closer to her father.
• Man Yeung
• Yu Yang as the father of Cheung Kei-sang who was killed by the Japanese Soldiers along with his young son.
• Helena Law as a village old lady
• Eric Li as a Kuomintang special agent, supervisor of Chau Sai-kai
• King Kong as Japanese military commander, brother-in-law of Suzuki Kazu who was used by him to reach his goals.

After the critical and commercial success of second installment No Regrets, TVB encouraged Lee to produce a third installment. Though Lee was initially against the idea, he agreed to helm the project if head writer and assistant creative director from the previous two installments, Cheung Wah-biu, would return to TVB after leaving in 2010.[8] Upon learning that Cheung was tied to other projects, Lee put the production of No Reserve on hold, expressing that without Cheung, he would be unable to continue the franchise.[9]

In December 2011, Lee announced that he would consider retirement after finishing the post-production work of his crime serial, Bullet Brain.[10] Lee admitted that the unsatisfying ratings from his 2011 drama, Bottled Passion, significantly impacted this decision.[11] Despite his hopes for retirement, TVB contacted Lee for a contract renewal in late 2012. Lee ultimately renewed his TVB contract in the spring of 2012 after TVB agreed to increase his pay and reduce his workload to one drama serial per year.[12]

Lee began pre-production work on No Reserve in September 2012. Lee's longtime collaborator and Bullet Brain head writer, Ip Kwong-yam, was attached to the script.[2] No Reserve was Ip's first TVB drama since leaving the company sixteen years prior. Ip drafted a preliminary script for No Reserve in May 2012 and began officially working on the project after the completion of Bullet Brain in August 2012. The Chinese working title of No Reserve was announced to be "Dip Hyut Chi Hung" (Chinese: 諜血雌雄; lit. 'Espionage Heroes'). The title was later changed to "Dip Hyut Cheung Tin" (Chinese: 諜血長天; lit. 'espionage through continuous time').

A costume fitting press conference was held on February 20, 2013. Principal photography began on March 11 in Hong Kong. Other filming locations included Foshan and Zhongshan.[13] A blessing ceremony was held on April 8. Filming wrapped up in July 2013.

The success of Rosy Business and No Regrets relaunched the careers of main leads, Sheren Tang and Wayne Lai. Both leads respectively won best actress and actor at the TVB Anniversary Awards two years in a row for their acclaimed performances. In late 2011, Lai stated that he would be willing to push aside other filming offers in order to accommodate his schedule to film No Reserve. Lai reconfirmed this statement with the Singaporean media in July 2012.[12] Tang also privately agreed to help Lee in No Reserve if her schedule allowed.[14]

When the No Reserve project was announced to be reopened in September 2012, Lai re-confirmed his return. A few days later, Lee announced that Myolie Wu would replace Tang as the serial's lead actress.[15] With the exception of Lai, a core star to the franchise, Lee indicated that No Reserve would feature an entirely younger and fresher cast.[15] Lee received a lot of complaints on Wu's casting; the complaints said that Tang had an irreplaceable role in the Rosy Business franchise. When asked about it, Tang said that her schedule was booked and Lee explained he did not know how to produce another drama with both Lai and Tang after two incredibly successful stories. Wu's acting abilities were questioned by audiences. Lee defended Wu, gushing that Wu was a TVB fadan he wanted to collaborate with the most.[15]

Following Wu's casting, Lee announced that Edwin Siu had been cast as the serial's second male lead. Natalie Tong and Sire Ma were also announced to have joined, but Tong left the cast in early 2013 due to schedule conflicts.[16]

A sales presentation trailer was filmed in October 2012 and released in December to mixed reviews, with many thinking it was too similar to No Regrets. Helena Law, Yoyo Chen, Eric Li, Cheung Kwok-keung, and returning cast members Susan Tse and Li Shing-cheong were confirmed to join the cast in February 2013.[17]